Orthogonal sp3-Ge/B Bimetallic Modules: Enantioselective Construction and Enantiospecific Cross-Coupling.

In this study, a series of enantioenriched sp3-Ge/B bimetallic modules were successfully synthesized via an enantioselective copper-catalyzed hydroboration of carbagermatrane (Ge)-containing alkenes. Orthogonal cross-coupling selectivity under different Pd-catalyzed conditions was achieved in an enantiospecific manner. Notably, the chiral secondary Ge exhibited a remarkable transmetallation ability prior to primary or secondary Bpin. The effectiveness of this Ge/B bimetallic strategy was further demonstrated through the development of new functional small molecules with Aggregation-Induced Emission (AIE) and Circularly Polarized Luminescence (CPL) performance. This represents the first successful example of synthesis of enantioenriched alkylgermanium reagents that permit enantiospecific cross-coupling reactions.

Tertiary cyclopropyl carbagermatranes: synthesis and cross-coupling.

The construction of the cyclopropyl quaternary carbon center can afford a series of 1,1-olefin bioisosteres. Here, we report tertiary cyclopropyl carbagermatranes, which can be easily obtained by the zinc-mediated decarboxylation of NHP esters. In addition, they exhibit efficient reactivity in the palladium-catalyzed cross-coupling reaction and orthogonal reactivity with boron reagents, therefore acting as robust nucleophiles for the synthesis of tertiary cyclopropane and efficient intermediates for the formation of quaternary centers.

[Effects of dazomet fumigation on growth, biological characteristics of Malus hupehensis seedlings and soil environment]. / 棉隆熏蒸处理对平邑甜茶幼苗生长和生物学特性及土壤环境的影响.

In this study, we examined the effects of dazomet fumigation with different concentrations (0, 0.1, 0.2, 0.4 g·kg-1) on the microbial characteristics of continuous cropping soil and growth of Malus hupehensis seedling in greenhouse and open-field pot. The results showed that all the treatment of dazomet fumigation could promote the growth of M. hupehensis seedlings in continuous cropping soil, with 0.2 g·kg-1 treatment showing the strongest effect. Compared to the control, plant height, stem diameter, dry weight of M. hupehensis seedlings in 0.2 g·kg-1 dazomet fumigation were increased by 192.9% and 91.8%, 72.8% and 60.1%, 196.8% and 195.0%, 138.5% and 130.7%, respectively in greenhouse and open-field. The root related indices (root length, root area, root volume, root respiration rate) were significantly promoted. The activities of SOD, POD, CAT in roots were increased by 114.6% and 118.5%, 123.5% and 107.6%, 164.6% and 175.6% respectively compared with the control, whereas the content of malondialdehyde was significantly lowered. Soil bacterial content, fungal content, copy number of Fusarium oxysporum gene and soil enzyme activity were significantly decreased with the increasing dazomet concentrations. In conclusion, 0.2 g·kg-1 dazomet fumigation could increase the biomass of M. hupehensis seedlings in continuous cropping, improve soil environment, and effectively alleviate the continuous cropping obstacle. Therefore, 0.2 g ·kg-1 dazomet fumigation could be given priority during the reconstruction of old apple orchards.

Zn-mediated decarboxylative carbagermatranation of aliphatic N-hydroxyphthalimide esters: evidence for an alkylzinc intermediate.

Alkyl nucleophiles synthesized by decarboxylation of the corresponding N-hydroxyphthalimide esters (NHP esters) would inherit the complex structure of natural carboxylic acids and result in useful cross-coupling fragments. Herein, we report the synthesis of alkyl carbagermatranes via Zn-mediated decarboxylation of NHP esters without Ni catalysis or photocatalysis. Mechanistic studies indicate that an alkyl zinc intermediate was involved; however, the generation of alkyl zinc will be inhibited in the presence of Ni. Hence, this study provides valuable resolution to the perplexing problem about whether organozinc was involved in recently emerging catalytic systems of NHP ester-Zn. Meanwhile, alkyl zinc reagents from NHP esters are compatible with aryl/alkyl bromides and iodides; therefore the scope of carbagermatranation in this work precedes that of in situ-generated organozinc from alkyl halides.

Alkylation-Terminated Catellani Reactions Using Alkyl Carbagermatranes.

The Catellani reaction has received substantial attention because it enables rapid multiple derivatization on aromatics. While using alkyl electrophiles to achieve ortho-alkylation was one of the earliest applications of the Catellani reaction, ipso-alkylation-terminated reactions with ß-H-containing reactants has not been realized to date. Herein, we report alkylation-terminated Catellani reaction using alkyl carbagermatranes (abbreviated as alkyl-Ge) as nucleophiles. The reactivity of alkyl-Ge and alkyl-B(OH)2 in this reaction is discussed. This approach enables efficient dialkylation with ß-H-containing reactants, which was previously inaccessible by Catellani reactions.

Alkyl Carbagermatranes Enable Practical Palladium-Catalyzed sp2-sp3 Cross-Coupling.

Pd-catalyzed cross-coupling reactions have achieved tremendous accomplishments in the past decades. However, C(sp3)-hybridized nucleophiles generally remain as challenging coupling partners due to their sluggish transmetalation compared to the C(sp2)-hybridized counterparts. While a single-electron-transfer-based strategy using C(sp3)-hybridized nucleophiles had made significant progress recently, fewer breakthroughs have been made concerning the traditional two-electron mechanism involving C(sp3)-hybridized nucleophiles. In this report, we present a series of unique alkyl carbagermatranes that were proven to be highly reactive in cross-coupling reactions with our newly developed electron-deficient phosphine ligands. Generally, secondary alkyl carbagermatranes show slightly lower, yet comparable activity to its Sn analogue. Meanwhile, primary alkyl carbagermatranes exhibit high activity, and they were also proved stable enough to be compatible with various reactions. Chiral secondary benzyl carbagermatrane gave the coupling product under base/additive-free conditions with its configuration fully inversed, suggesting that transmetalation was carried out in an "SE2(open) Inv" pathway, which is consistent with Hiyama's previous observation. Notably, the cross-coupling of primary alkyl carbagermatranes could be performed under base/additive-free conditions with excellent functional group tolerance and therefore may have potentially important applications such as stapled peptide synthesis.

Directing Group in Decarboxylative Cross-Coupling: Copper-Catalyzed Site-Selective C-N Bond Formation from Nonactivated Aliphatic Carboxylic Acids.

Copper-catalyzed directed decarboxylative amination of nonactivated aliphatic carboxylic acids is described. This intramolecular C-N bond formation reaction provides efficient access to the synthesis of pyrrolidine and piperidine derivatives as well as the modification of complex natural products. Moreover, this reaction presents excellent site-selectivity in the C-N bond formation step through the use of directing group. Our work can be considered as a big step toward controllable radical decarboxylative carbon-heteroatom cross-coupling.

[Allogeneic hematopoietic stem cell transplantation for the treatment of mucopolysaccharidosis type 1: a case report].

Mucopolysaccharidosis type I (MPS-I) is an inborn error of metabolism with progressive multisystem involvement. Hurler syndrome is the most severe form of MPS-I that causes progressive deterioration of the central nervous system with ensuing death. This study reported the therapeutic effect of allogeneic hematopoietic stem cell transplantation (allo-HSCT) on Hurler syndrome in one case. The patient was a 25-month-old boy. He underwent allo-HSCT. The donor was his elder sister whose HLA-B locus was not matching. The reduced-intensity of BuCy conditioning regimen in allo-HSCT for this patient was as follows: busulfan 3.7 mg/kg daily at 9 to 6 days before transplantation, cyclophosphamide 42.8 mg/kg daily at 5 to 2 days before transplantation, and rabbit antithymocyte globulin 3.5 mg/kg daily at 1, 3, 5, and 7 days before transplantation. Human granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (CD34+ cells 12.8 x10(6)/kg) were infused and cyclosporine (CSA), short-course methotrexate, daclizumab and mycophenolate mofetil (MMF) were administered to prevent graft-versus-host disease (GVHD). Complete donor-type engraftment was confirmed by Short Tandem Repeat-Polymerase Chain Reaction (STR-PCR) on day 14 after transplantation. Neutrophil and platelet engraftment occurred on days 11 and 19 after transplantation respectively. Only grade I regimen-related toxicity of live and gastrointestinal tract occurred. GVHD and graft failure were not observed. After transplantation, the clinical symptoms and the neurocognitive function were greatly improved in this patient. It was concluded that allo-HSCT was effective for the treatment of MPS-I. The reduced-intensity conditioning regimen was helpful to decrease the regimen-related toxicity. Sufficient immunosuppressive therapy and adequate hematopoietic stem cells infusion may be beneficial to the donor cell engraftment and reducing the incidence of graft failure and GVHD.