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1.
Org Lett ; 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34636575

RESUMO

Herein, a series of new 8-OIQ cobalt complexes were synthesized and used for cobalt-catalyzed chemo- and enantioselective 1,4-hydroboration of enones with HBpin to access chiral ß,ß-disubstituted ketones with good to excellent chemo- and enantioselectivties. This protocol is operationally simple and shows a broad substrate scope.

2.
J Card Surg ; 36(10): 3607-3618, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34338370

RESUMO

BACKGROUND: Little is known regarding whether hyperoxic reoxygenation was associated with higher risk of cardiovascular disorder following tetralogy of Fallot repair. METHODS: We performed a nested case-control study among patients aged 1 month-18 years undergoing complete repair of tetralogy of Fallot in 2012-2018. We measured the highest perfusate oxygenation (PpO2) during aortic occlusion in 107 cardiovascular disorder cases and in 321 controls matched 1:3 to the cases on date of surgery, sex, and area of residence. We analyzed the association between PpO2 and outcome using multivariable conditional logistic regression adjusted for covariates. We further identified and integrated the risk covariates to build prediction nomograms. RESULTS: Cases had higher percentage of exposure to PpO2 > 200 mmHg (86.0% vs. 76.1%, p = .019) than controls. Patients with PpO2 > 200 mmHg had an increased risk of cardiovascular disorder compared to those with PpO2 ≤ 200 mmHg (odd ratio [OR] = 2.075, 95% confidence interval [CI] = 1.035, 4.158, p = .039) adjusted for matching, clinical and procedural covariates. Categorical PpO2, lower body mass index, lower SpO2, untreated minor aortopulmonary collateral arteries, high immediately postoperative central venous pressure, and longer cardiopulmonary bypass time were independent risk factors for cardiovascular disorder (all p < .05). Combining PpO2 nomogram slightly improved discrimination compared with covariate-based nomogram alone for training cohort (area under receiver operating characteristic curve [AUC] = 0.768 vs. 0.761) and for internal validation (AUC = 0.759 vs. 0.753). CONCLUSION: Our findings suggest association exists between high PpO2 during aortic occlusion and cardiovascular disorder risk, and nomogram integrating clinical and procedural factors may be useful in management of patients with tetralogy of Fallot.


Assuntos
Tetralogia de Fallot , Estudos de Casos e Controles , Criança , Estudos de Coortes , Humanos , Lactente , Nomogramas , Fatores de Risco , Tetralogia de Fallot/cirurgia
3.
Angew Chem Int Ed Engl ; 60(41): 22454-22460, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34347353

RESUMO

Regiodivergent addition reactions provide straightforward and atom-economic approaches to access different regioisomers. However, the regio-chemistry control to access all the possible results is still challenging especially for the reaction involving multiple addition steps. Herein, we reported regio-controllable cobalt-catalyzed sequential hydrosilylation/hydroboration of arylacetylenes, delivering all the possible regio-outcomes with high regioselectivities (up to >20/1 rr for all the cases). Each regioisomer of value-added silylboronates could be efficiently and regioselectively obtained from the same materials. The adjustment of the ligands of cobalt catalysts combined with dual catalysis relay strategy is the key to achieve regio-chemistry control. This regio-controllable research might inspire the exploration of the diversity-oriented synthesis that involves multiple additions and provide full sets of regioisomers of other synthetic useful molecules.

4.
Insect Sci ; 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34414659

RESUMO

Validamycin, as a broadly applied antibiotic, has been used to control rice sheath blight disease. Furthermore, validamycin was considered as an insecticide to control agricultural pests. Insight into the mechanism of validamycin's action on insects can provide molecular targets for the control of agricultural pests. In this study, a toxicological test analysis revealed that Spodoptera litura larval growth and development was significantly inhibited and the pupation rate was significantly reduced with the increase of the concentration of validamycin. According to the NMR-based metabolomic analysis, a total of 15 metabolites involved in glycolysis and tricarboxylic acid cycle (TCA) pathways were identified. Additionally, trehalase activities, glucose and chitin contents were significantly downregulated, but the trehalose content was upregulated after exposure to validamycin. Reverse transcription quantitative PCR analysis revealed that the expression level of genes involved in glycolysis, TCA and chitin synthesis were upregulated after treating with validamycin. Further chitin staining also confirmed that chitin content was downregulated at 12 h after validamycin treatment. Our results indicated that validamycin worked via two different molecular mechanisms, one through inhibiting glycometabolism and the other by inhibiting chitin synthesis in S. litura. The information lays a theoretical foundation for further control of S. litura.

5.
J Am Chem Soc ; 143(32): 12433-12438, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34343425

RESUMO

Here, we reported for the first time an iron-catalyzed highly enantioselective hydrogenation of minimally functionalized 1,1-disubstituted alkenes to access chiral alkanes with full conversion and excellent ee. A novel chiral 8-oxazoline iminoquinoline ligand and its iron complex have been designed and synthesized. This protocol is operationally simple by using 1 atm of hydrogen gas and shows good functional group tolerance. A primary mechanism has been proposed by the deuterium-labeling experiments.

6.
Acc Chem Res ; 54(11): 2701-2716, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34011145

RESUMO

Transition metal catalyzed asymmetric hydrofunctionalization of readily available unsaturated hydrocarbons presents one of the most straightforward and atom-economic protocols to access valuable optically active products. For decades, noble transition metal catalysts have laid the cornerstone in this field, on account of their superior reactivity and selectivity. In recent years, from an economical and sustainable standpoint, first-row, earth-abundant transition metals have received considerable attention, due to their high natural reserves, affordable costs, and low toxicity. Meanwhile, the earth-abundant metal catalyzed hydrofunctionalization reactions have also gained much interest and been investigated gradually. However, since chiral ligand libraries for earth-abundant transition-metal catalysis are limited to date, the development of highly enantioselective versions remains a significant challenge.This Account summarizes our recent efforts in developing suitable chiral ligands for iron and cobalt catalysts and their applications in the highly enantioselective hydrofunctionalization reactions (hydroboration and hydrosilylation) of alkenes and alkynes. In ligand design, we envisioned that chiral unsymmetric NNN-tridentate (UNT) ligand scaffolds could promote these enantioselective transformations with earth-abundant metals. Therefore, several types of chiral UNT ligands were designed and prepared in our laboratory, utilizing readily available natural amino acids as chiral sources. In the very beginning, chiral oxazoline iminopyridine (OIP) ligands were proposed and investigated through the rational combination of nitrogen-containing ligand scaffolds. After a systematic survey of the ligand effects, the imine moiety in the rigid OIP ligands was replaced by a conformationally more flexible amine unit, leading to the construction of reactive oxazoline aminoisopropylpyridine (OAP) ligands. Subsequently, imidazoline iminopyridine (IIP) and thiazoline iminopyridine (TIP) ligands were prepared by altering the oxygen atom of oxazoline with nitrogen and sulfur linkers, respectively. To further expand the chiral ligand library, other tridentate ligands containing a twisted pincer, anionic, and nonrigid backbone were also designed and synthesized, including iminophenyl oxazolinyl phenylamine (IPOPA) and imidazoline phenyl picolinamide (ImPPA). The efficacy of these chiral UNT ligands for asymmetric induction in iron and cobalt catalysis has been demonstrated through asymmetric hydrofunctionalization of alkenes and asymmetric sequential hydrofunctionalization of alkynes, which exhibit excellent reactivity as well as high chemo-, regio-, and stereoselectivity with broad functional group tolerance. Notably, highly regio- and enantioselective hydrofunctionalization of challenging substrates, such as 1,1-disubstituted aryl alkenes and terminal aliphatic alkenes, was also achieved. Furthermore, the development of asymmetric sequential isomerization/hydroboration of internal alkenes and sequential hydrofunctionalization of alkynes further demonstrates the synthetic power of these catalytic systems. The chiral enantioenriched products obtained by these methodologies could be potentially utilized in organic synthesis, medicinal chemistry, and materials science. We believe that our continuous efforts in this field would be beneficial to the development of asymmetric earth-abundant metal catalysis.

7.
Aging (Albany NY) ; 13(8): 12239-12257, 2021 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-33872218

RESUMO

Endothelial dysfunction, and the differentiation of smooth muscle cells (SMCs) into proliferative, secretory phenotypes, are two major pathophysiological processes in atherosclerosis. SMCs have the potential to recruit macrophages in atherosclerotic plaques, in which macrophages drive inflammatory responses. In this study, we found that microRNA-503-5p (miR-503-5p) was enriched in either extracellular vesicles (EVs), secreted by oxidized low-density lipoprotein-treated macrophages, or the EVs from peripheral blood mononuclear cells of atherosclerosis patients. miR-503-5p was transferred intercellularly from macrophages to the co-cultured human coronary artery endothelial cells (HCAECs) and HCASMCs via EVs, thus reducing the proliferative and angiogenic abilities of HCAECs and accelerating the proliferative and migrating abilities of HCASMCs. Smad family members 1, 2 and 7 were negatively regulated by miR-503-5p in HCAECs and HCASMCs. miR-503-5p was verified as an enhancer of inflammatory cytokines and adhesion molecules released by macrophages, in part via the down-regulation of smad family members 1, 2 and 7. The inhibition of miR-503-5p by lentivirus reduced atherosclerotic lesion formations in the aorta of atherosclerotic mice. Our work demonstrated a miR-503-5p- and EV-mediated mechanism for macrophage communication with HCAECs and HCASMCs in atherosclerosis. miR-503-5p is pro-atherosclerotic stimuli that may be a therapeutic target for atherosclerosis treatment.


Assuntos
Aterosclerose/imunologia , Comunicação Celular/genética , Vesículas Extracelulares/metabolismo , Macrófagos/imunologia , MicroRNAs/metabolismo , Adulto , Animais , Aterosclerose/sangue , Aterosclerose/genética , Aterosclerose/patologia , Comunicação Celular/imunologia , Movimento Celular/genética , Movimento Celular/imunologia , Proliferação de Células/genética , Técnicas de Cocultura , Vasos Coronários/citologia , Vasos Coronários/patologia , Modelos Animais de Doenças , Células Endoteliais/citologia , Células Endoteliais/imunologia , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/patologia , Feminino , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Lipoproteínas LDL/imunologia , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Knockout para ApoE , Pessoa de Meia-Idade , Miócitos de Músculo Liso , Cultura Primária de Células , Células RAW 264.7 , Células THP-1
8.
BMC Cardiovasc Disord ; 21(1): 210, 2021 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-33902450

RESUMO

BACKGROUND: Little is known regarding the effect of cardiopulmonary bypass (CPB) reoxygenation on cardiac function following tetralogy of Fallot repair. We hypothesized that hyperoxic reoxygenation would be more strongly associated with myocardial dysfunction in children with tetralogy of Fallot. METHODS: We investigated the association of perfusate oxygenation (PpO2) associated with myocardial dysfunction among children aged 6-72 months who underwent complete repair of tetralogy of Fallot in 2012-2018. Patients were divided into two groups: lower PpO2 group (≤ 250 mmHg) and higher PpO2 (> 250 mmHg) group based on the highest value of PpO2 during aortic occlusion. The odd ratio (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression models. RESULTS: This study included 163 patients perfused with lower PpO2 and 213 with higher PpO2, with median age at surgery 23.3 (interquartile range [IQR] 12.5-39.4) months, 164 female (43.6%), and median body mass index 15.59 (IQR 14.3-16.9) kg/m2. After adjustment for baseline, clinical and procedural variables, patients with higher PpO2 were associated with higher risk of myocardial dysfunction than those with lower PpO2 (OR 1.770; 95% CI 1.040-3.012, P = 0.035). Higher PpO2, lower SpO2, lower pulmonary annular Z-score, and longer CPB time were independent risk factors for myocardial dysfunction. CONCLUSIONS: Association exists between higher PpO2 and myocardial dysfunction risk in patients with tetralogy of Fallot, highlighting the modulation of reoxygenation during aortic occlusion to reduce cardiovascular damage following tetralogy of Fallot repair. TRIAL REGISTRATION: Clinical Trials. gov number NCT03568357. June 26, 2018.

9.
Angew Chem Int Ed Engl ; 60(2): 690-694, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-32970357

RESUMO

A cobalt-catalyzed Markovnikov-type hydroboration of terminal alkynes with HBpin to access α-alkenyl boronates with good regioselectivity and atom economy is reported. A new ligand has been developed for the cobalt hydride catalyst that has been used for a unique Markovnikov selective insertion of terminal alkynes into metal hydride bond. This operationally simple protocol exhibits excellent functional group tolerance to deliver valuable alkene derivatives.

10.
Insect Sci ; 28(3): 718-734, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32428381

RESUMO

The Asian citrus psyllid, Diaphorina citri is the principal vector of huanglongbing, which transmits Candidatus Liberibacter asiaticus. Trehalase is a key enzyme involved in trehalose hydrolysis and plays an important role in insect growth and development. The specific functions of this enzyme in D. citri have not been determined. In this study, three trehalase genes (DcTre1-1, DcTre1-2, and DcTre2) were identified based on the D. citri genome database. Bioinformatic analysis showed that DcTre1-1 and DcTre1-2 are related to soluble trehalase, whereas DcTre2 is associated with membrane-bound trehalase. Spatiotemporal expression analysis indicated that DcTre1-1 and DcTre1-2 had the highest expression levels in the head and wing, respectively, and DcTre2 had high expression levels in the fat body. Furthermore, DcTre1-1 and DcTre1-2 expression levels were induced by 20-hydroxyecdysone and juvenile hormone Ⅲ, but DcTre2 was unaffected. The expression levels of DcTre1-1, DcTre1-2, and DcTre2 were significantly upregulated, which resulted in high mortality after treatment with validamycin. Trehalase activities and glucose contents were downregulated, but the trehalose content increased after treatment with validamycin. In addition, the expression levels of chitin metabolism-related genes significantly decreased at 24 and 48 h after treatment with validamycin. Furthermore, silencing of DcTre1-1, DcTre1-2, and DcTre2 reduced the expression levels of chitin metabolism-related genes and led to a malformed phenotype of D. citri. These results indicate that D. citri trehalase plays an essential role in regulating chitin metabolism and provides a new target for control of D. citri.


Assuntos
Hemípteros , Trealase , Animais , Quitina/metabolismo , Regulação da Expressão Gênica , Genes de Insetos , Hemípteros/genética , Hemípteros/metabolismo , Inositol/análogos & derivados , Inositol/farmacologia , Controle de Pragas , Interferência de RNA , Trealase/efeitos dos fármacos , Trealase/genética , Trealase/metabolismo , Trealose/metabolismo
11.
Insect Sci ; 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33118290

RESUMO

Validamycin has been widely used as a specific competitive inhibitor of trehalase. In our previous research, validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri, resulting in abnormal phenotypes. However, the mechanism of validamycin's action on D. citri remains unclear. Here, using a comparative transcriptome analysis, 464 differentially expressed genes (DEGs) in D. citri were identified after validamycin treatment. A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in "small molecule process", "structural molecule activity" and "transition metal ion binding". DEGs involved in chitin metabolism, cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction. The RNA interference of D. citri chitinase-like protein ENO3 and D. citri cuticle protein 7 genes significantly affected D. citri molting. Moreover, the recombinant chitinase-like protein ENO3 exhibited a chitin-binding property, and an antimicrobial activity against Bacillus subtilis. This study provides a first insight into the molecular changes in D. citri after exposure to validamycin and identifies two effective RNA interference targets for D. citri control.

12.
Biomed Res Int ; 2020: 7248513, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32802872

RESUMO

Drought is a limiting factor for cotton productivity and quality. Irrigation could increase cotton yield. This study is aimed at formulating a proper irrigation depth for cotton at China' Inner Mongolia and at investigating the molecular mechanism underlying the difference induced by irrigation. Transcriptomic analysis was carried out to reveal the global transcriptome profiles on the leaves of cotton seedlings (G. hirsutum L. cv. "Zhongmian 92") with trace irrigation tapes at 30 cm (D30) and 50 cm (D50) underground. The differentially expressed genes (DEGs) were identified and clustered by functional enrichment analysis. The results showed that no significant differences were found in the lint percentage. The yields of unpinned and lint cotton were increased by the D30 regime but decreased by the D50 regime. Transcriptomic analysis showed that 4,549 nonoverlapped DEGs were identified by comparative analysis. Transcription factors, including bZIP, WARK, Myb, and NAC, were altered between D50 and D30. The D50 regime induced more DEGs compared with the D30 regime, which was associated with plant tolerance to abiotic stresses and drought. In conclusion, trace irrigation at 30 cm underground was suitable for cotton irrigation at China's Inner Mongolia, while the D50 irrigation regime influenced the cotton yield via drought stress in cotton plants.


Assuntos
Irrigação Agrícola , Regulação da Expressão Gênica de Plantas , Gossypium , Proteínas de Plantas , Estresse Fisiológico , Transcriptoma , Gossypium/genética , Gossypium/metabolismo , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética
13.
J Am Chem Soc ; 142(34): 14455-14460, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32787242

RESUMO

Here, we reported for the first time a mechanistically distinctive cobalt-catalyzed Markovnikov-type sequential semihydrogenation/hydrohydrazidation of aliphatic terminal alkynes in one pot. A cobalt hydride species was employed as two roles for both a unique metal-catalyzed Markovnikov-type insertion of the aliphatic terminal alkynes and then metal-catalyzed hydrogen atom transfer of alkenes. This operationally simple protocol exhibits excellent functional group tolerance and step economy. The hydrazone products could be easily transferred to various valuable amine derivatives.

14.
Zhongguo Gu Shang ; 33(4): 383-7, 2020 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-32351097

RESUMO

Discoid meniscus injury is a kind of common sports injury. Its treatment methods include arthroscopic discoid meniscus plasty, discoid meniscus subtotal resection, discoid meniscus total resection and so on. Although the short-term clinical effect is good, the long-term clinical effect is not ideal. At present, different scholars have different views on the choice of surgical methods for discoid meniscus injury. In recent years, many scholars have shown that the choice of operation and the change of lower limb force line are related to the therapeutic effect of discoid meniscus injury. This paper mainly summarizes the current situation of the treatment of discoid meniscus injury and the changes of the force line of the lower limbs after operation, and expounds therole of the evaluation of the force line of the lower limbs in the treatment of discoid meniscus, so as to provide the basis for the clinical individualized treatment of discoid meniscus injury.


Assuntos
Articulação do Joelho , Lesões do Menisco Tibial , Artroscopia , Humanos , Extremidade Inferior , Meniscos Tibiais
15.
iScience ; 23(4): 100985, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32240952

RESUMO

An iron-catalyzed highly anti-Markovnikov selective, enantioselective hydrosilylation of vinylcyclopropanes with PhSiH3 was reported for the preparation of valuable chiral allylic silanes via stereospecific C-C bond cleavage. Simultaneously, difficultly prepared chiral VCPs could be also obtained with moderate to excellent enantioselectivity via this kinetic resolution pathway. The chiral Z-allylic silanes could be converted to various chiral allylic derivatives. A possible mechanism via an iron-silyl species was proposed based on experimental and computational studies.

16.
Insects ; 11(4)2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32316461

RESUMO

Chitin is one the main components of the insect cuticle, and chitin synthase (CHS) is an important enzyme required for chitin formation. CHS has been characterized in various insect species, but the structure and biochemical properties in Spodoptera litura have not been determined. In this study, we identified two CHS genes, SlCHS1 and SlCHS2, which encode proteins with 1565 and 1520 amino acid residues, respectively. Transcriptional analysis suggested that SlCHS1 has a high expression level in the integument whereas SlCHS2 showed the highest expression level in the midgut. During S. litura growth and development, SlCHS1 and SlCHS2 were both predominantly expressed in the fourth-instar larval stage. In addition, the expression of SlCHS1 and SlCHS2 could be induced by 20-hydroxyecdysone (20E). Silencing of SlCHS1 by RNA interference significantly inhibited the pupation and molting of S. litura larvae (RNAi), while knockdown of SlCHS2 had no significant effects on the S. litura phenotype. These results may provide a new molecular target for control of S. litura.

17.
Org Lett ; 22(7): 2532-2536, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32202788

RESUMO

A highly enantioselective cobalt-catalyzed hydroboration of diaryl ketones with pinacolborane was developed using chiral imidazole iminopyridine as a ligand to access chiral benzhydrols in good to excellent yields and ee. This protocol could be carried out in a gram scale under mild reaction conditions with good functional group tolerance. Chiral biologically active 3-substituted phthalide and (S)-neobenodine could be easily constructed through asymmetric hydroboration as a key step.

18.
Insects ; 11(3)2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32156093

RESUMO

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important transmission vector of the citrus greening disease Candidatus Liberibacter asiaticus (CLas). The D. citri midgut exhibits an important tissue barrier against CLas infection. However, the molecular mechanism of the midgut response to CLas infection has not been comprehensively elucidated. In this study, we identified 778 differentially expressed genes (DEGs) in the midgut upon CLas infection, by comparative transcriptome analyses, including 499 upregulated DEGs and 279 downregulated DEGs. Functional annotation analysis showed that these DEGs were associated with ubiquitination, the immune response, the ribosome, endocytosis, the cytoskeleton and insecticide resistance. KEGG enrichment analysis revealed that most of the DEGs were primarily involved in endocytosis and the ribosome. A total of fourteen DEG functions were further validated by reverse transcription quantitative PCR (RT-qPCR). This study will contribute to our understanding of the molecular interaction between CLas and D. citri.

19.
Foods ; 9(2)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32054037

RESUMO

Proximate composition and starch nutritional properties of twenty cooked lentils were assessed to identify unique varieties that could be used in value added foods. Significant variations exist among the lentil varieties (p < 0.05) with respect to their energy, fat, protein, carbohydrate, and dietary fiber content, and these are related to lentil type and seed size. Dazil and Greenstar were unique for their high resistant starch content (RS) and lower area under the starch hydrolysis curve (SHAUC) while Proclaim was opposite. SHAUC was positively correlated (p < 0.001) with rapidly digestible starch (RDS) content (r = 0.626) but negatively correlated with RS content (r = -0.635). Principal component analysis showed that the first three principal components accounted for 62.8% of the total variance and the contribution of SHAUC was 33.2%. These results confirm that in vitro SHAUC and a combination of RDS and RS may be predictive of the digestibility profile of cooked lentils.

20.
Nat Commun ; 11(1): 783, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034130

RESUMO

Highly regio- and enantioselective intermolecular hydroamination of alkenes is a challenging process potentially leading to valuable chiral amines. Hydroamination of alkenes via metal-catalyzed hydrogen atom transfer (HAT) with good regioselectivity and functional group tolerance has been reported, however, high enantioselectivity has not been achieved due to the lack of suitable ligands. Here we report a ligand-promoted cobalt-catalyzed Markovnikov-type selective radical hydroamination of alkenes with diazo compounds. This operationally simple protocol uses unsymmetric NNN-tridentate (UNT) ligand, readily available alkenes and hydrosilanes to construct hydrazones with good functional group tolerance. The hydrazones can undergo nitrogen-nitrogen bond cleavage smoothly to deliver valuable amine derivatives. Additionally, asymmetric intermolecular hydroamination of unactivated aliphatic terminal alkenes using chiral N-imidazolinylphenyl 8-aminoquinoline (IPAQ) ligands has also been achieved to afford chiral amine derivatives with good enantioselectivities.

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