ABSTRACT
A boron-catalyzed Michael reaction using pairs of carboxylic acids was developed. The reaction occurs through dual activation of the two substrates by a boron catalyst, which facilitates boron enolate formation from the donor carboxylic acid with simultaneous activation of the α,ß-unsaturated carboxylic acid as the acceptor. α-Aryl and α-alkenyl carboxylic acids were applicable as donors. The versatility and utility of this reaction were demonstrated by the direct use of pharmaceuticals as donor carboxylic acids.
ABSTRACT
OBJECTIVE: To evaluate in-hospital fees and surgical outcomes of robot-assisted radical cystectomy (RARC), laparoscopic radical cystectomy (LRC) and open radical cystectomy (ORC) using a Japanese nationwide database. METHODS: All data were obtained from the Diagnosis Procedure Combination database between April 2020 and March 2022. Basic characteristics and perioperative indicators, including in-hospital fees, were compared among the RARC, LRC and ORC groups. Propensity score-matched comparisons were performed to assess the differences between RARC and ORC. RESULTS: During the study period, 2931, 1311 and 2435 cases of RARC, LRC and ORC were identified, respectively. The RARC group had the lowest in-hospital fee (median: 2.38 million yen), the shortest hospital stay (26 days) and the lowest blood transfusion rate (29.5%), as well as the lowest complication rate (20.9%), despite having the longest anesthesia time (569 min) among the three groups (all P < 0.01). The outcomes of LRC were comparable with those of RARC, and the differences in these indicators between the RARC and ORC groups were greater than those between the RARC and LRC groups. In propensity score-matched comparisons between the RARC and ORC groups, the differences in the indicators remained significant (all P < 0.01), with an ~50 000 yen difference in in-hospital fees. CONCLUSIONS: RARC and LRC were considered to be more cost-effective surgeries than ORC due to their superior surgical outcomes and comparable surgical fees in Japan. The widespread adoption of RARC and LRC is expected to bring economic benefits to Japanese society.
Subject(s)
Cystectomy , Laparoscopy , Robotic Surgical Procedures , Urinary Bladder Neoplasms , Humans , Cystectomy/economics , Cystectomy/methods , Robotic Surgical Procedures/economics , Robotic Surgical Procedures/statistics & numerical data , Male , Laparoscopy/economics , Laparoscopy/statistics & numerical data , Female , Japan , Aged , Urinary Bladder Neoplasms/surgery , Urinary Bladder Neoplasms/economics , Middle Aged , Length of Stay/statistics & numerical data , Length of Stay/economics , Treatment Outcome , Propensity Score , Postoperative Complications/epidemiology , Postoperative Complications/economics , East Asian PeopleABSTRACT
Photoinduced N-internal vicinal aminochlorination of styrene-type terminal alkenes was developed. The reaction proceeded without any catalyst, and the use of N-chloro(fluorenone imine) as both a photoactivatable aminating agent and a chlorinating agent was essential. The imine moiety, introduced at the internal position of the alkenes, could be hydrolyzed under mild conditions to provide versatile ß-chlorinated primary amines, the synthetic utility of which was demonstrated by several transformations.
Subject(s)
Alkenes , Amines , Catalysis , Light , Styrene , Hydrocarbons, Chlorinated/chemistryABSTRACT
Dystrophic calcification (DC) after transurethral resection of prostate (TURP) is rare. In our patient, bipolar TURP was performed by an experienced urologist, without complications. Seven months later, he developed a tingling urethral sensation, difficulty in urination, urgency, and perineal discomfort. Computed tomography (CT) showed a high-density area occupying the prostatic resection cavity. Re-surgery involved laser ablation of the DC. Two months later, the DC recurred. At the second re-surgery, the DC was removed without using electricity. Repeat CT at 13 months showed near complete disappearance of the DC. Wound healing might interrupt the vicious cycle of DC recurrence.
ABSTRACT
Postmating isolation is thought to be an important driver of the late stages of speciation. However, relatively little is empirically known about the process compared with other isolating mechanisms that drive the early stages of speciation, especially in non-model organisms. We characterized the genetic architecture of postmating isolation between 2 rockfishes, Sebastes schlegelii and S. trivittatus, whose reproductive isolation is complete. We examined transmission ratio distortion (TRD) patterns of genetic markers in 2 reciprocal backcross populations. Markers showing either of the 2 types of TRD was widespread across the genome, with some of the distorted markers forming extensive clusters around the recombination coldspots. These suggest that the postmating isolation effectively prevents gene flow across the genome and the recombination landscape contributes to the genetic architecture. Comparisons between 2 backcross families and 2 developmental stages showed little similarity in the distorted markers, suggesting asymmetry and stage specificity of the isolation. This may be due to hybrid incompatibility involving maternal factors or extrinsic selection. The lack of sex-ratio distortion in the mapping families suggested that Haldane's rule in terms of hybrid inviability does not hold. Additionally, quantitative trait loci (QTL) mapping detected significant QTLs for sex and the morphological traits relevant to speciation and convergence of rockfishes, including body coloration. Genes in the melanocortin system, including agouti-signaling protein 1 (asip1) and melanocortin 1 receptor (mc1r), might underlie the horizontal and vertical color patterns on the body, respectively. These findings constitute an essential step toward a comprehensive understanding of speciation and morphological diversification of rockfishes.
Subject(s)
Perciformes , Reproductive Isolation , Humans , Animals , Phenotype , Quantitative Trait Loci , Genetic Markers , Perciformes/genetics , Genetic Speciation , Hybridization, GeneticABSTRACT
BACKGROUND: Renal cell carcinoma (RCC) and non-small cell lung cancer (NSCLC) are representative malignancies that respond well to immune checkpoint inhibitors (ICIs). Research has been conducted to identify biomarkers, such as programmed death ligand-1 (PD-L1), that would allow the response to ICI therapy to be predicted; however, the complex tumor immune system consisting of both host and tumor factors may also exert an influence. CASE PRESENTATION: Computed tomographic imaging (CT) incidentally revealed a left renal mass, and a left pulmonary nodule with multiple lymph node metastases (LNMs). Firstly, video-assisted thoracic surgery revealed a lung tumor invading the chest wall. Histologically, the findings of the tumor were consistent with squamous cell carcinoma (SCC), and immunohistochemistry (IHC) showed positive PD-L1 expression. The renal tumor was excised by robotic-assisted partial nephrectomy (RAPN). Histologically, the renal tumor showed the features of clear cell carcinoma (CCC). Four months after the RAPN, CT revealed left hydronephrosis caused by an enhancing ureteral tumor. Then, multiple right lung metastases appeared, and the left lung tumor increased. Following treatment including atezolizumab, the primary lung SCC and the multiple LNMs almost disappeared completely, while the ureteral and right lung metastases showed progression. The ureteral metastasis was resected by left open nephroureterectomy. Histology of the ureteral tumor revealed features consistent with CCC. Histological examination of the multiple right lung metastases that were resected by partial lobectomy via a small thoracic incision also revealed features consistent with CCC. Two months after nephroureterectomy, a solitary left lung metastasis was treated by nivolumab and ipilimumab. Six months after nephroureterectomy, the patient died of RCC. Further studies of specimens revealed that the tumor cells in the primary RCC and the ureteral and lung metastases showed negative results of IHC for PD-L1. CONCLUSIONS: The responses to ICI therapy of concomitant RCC and NSCLC were quite different. The PD-L1 expression status in individual tumors in cases of multiple primary malignancies (MPMs) may directly predict the response of each malignancy to ICI therapy, because the host immune system, which may affect the response to ICI therapy, could be the same in MPMs.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Carcinoma, Renal Cell , Carcinoma, Squamous Cell , Kidney Neoplasms , Lung Neoplasms , Neoplasms, Multiple Primary , Robotic Surgical Procedures , Ureteral Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/pathology , Immune Checkpoint Inhibitors/therapeutic use , Carcinoma, Renal Cell/drug therapy , Carcinoma, Renal Cell/surgery , B7-H1 Antigen , Carcinoma, Squamous Cell/metabolism , Kidney Neoplasms/drug therapy , Kidney Neoplasms/surgery , Nephrectomy , Lung/pathologyABSTRACT
Catalytic, chemoselective, and asymmetric α-functionalizations of carboxylic acids promise up-grading simple feedstock materials to value-added functional molecules, as well as late-stage structural diversifications of multifunctional molecules, such as drugs and their leads. In this personal account, we describe boron-catalyzed α-functionalizations of carboxylic acids developed in our group (five reaction types). The reversible boron carboxylate formation is key to the acidification of the α-protons and enolization using mild organic bases, allowing for chemoselective and asymmetric bond formations of carboxylic acids. The ligand effects on reactivity and stereoselectivity, substrate scopes, and mechanistic insights are summarized.
Subject(s)
Boron , Carboxylic Acids , Carboxylic Acids/chemistry , Boron/chemistry , CatalysisABSTRACT
A high-quality genome assembly is imperative to explore the evolutionary basis of characteristic attributes that define chemotype and provide essential resources for a molecular breeding strategy for enhanced production of medicinal metabolites. Here, using single-molecule high-fidelity (HiFi) sequencing reads, we report chromosome-scale genome assembly for Chinese licorice (Glycyrrhiza uralensis), a widely used herbal and natural medicine. The entire genome assembly was achieved in eight chromosomes, with contig and scaffold N50 as 36.02 and 60.2 Mb, respectively. With only 17 assembly gaps and half of the chromosomes having no or one assembly gap, the presented genome assembly is among the best plant genomes to date. Our results showed an advantage of using highly accurate long-read HiFi sequencing data for assembling a highly heterozygous genome including its complexed repeat content. Additionally, our analysis revealed that G. uralensis experienced a recent whole-genome duplication at approximately 59.02 million years ago post a gamma (γ) whole-genome triplication event, which contributed to its present chemotype features. The metabolic gene cluster analysis identified 355 gene clusters, which included the entire biosynthesis pathway of glycyrrhizin. The genome assembly and its annotations provide an essential resource for licorice improvement through molecular breeding and the discovery of valuable genes for engineering bioactive components and understanding the evolution of specialized metabolites biosynthesis.
Subject(s)
Glycyrrhiza uralensis , Glycyrrhiza uralensis/genetics , Glycyrrhiza uralensis/metabolism , Chromosomes , Genome, Plant , Biosynthetic Pathways , Multigene FamilyABSTRACT
Corticotropin-releasing factor (CRF), a representative stress-related neuropeptide, in the central nervous system reportedly both facilitates and suppresses the micturition, therefore, roles of central CRF in regulation of the micturition are still controversial. In this study, we investigated (1) effects of intracerebroventricularly (icv)-administered CRF on the micturition, and (2) brain CRF receptor subtypes (CRFR1/CRFR2) and glutamatergic receptors (NMDA/AMPA subtypes) involved in the CRF-induced effects in male Wistar rats under urethane anesthesia. Intercontraction intervals (ICI), and maximal voiding pressure (MVP), were evaluated by continuous cystometry 45 min before CRF administration or intracerebroventricular pretreatment with other drugs as follows and 3 h after CRF administration. Single-voided volume (Vv), post-voiding residual volume (Rv), bladder capacity (BC), and voiding efficiency (VE) were evaluated by single cystometry 60 min before CRF administration and 60-120 min after the administration. Icv-administered CRF reduced ICI, Vv, and BC without changing MVP, Rv, or VE. The CRF-induced ICI reduction was attenuated by icv-pretreated CP154526 (CRFR1 antagonist), MK-801 (NMDA receptor antagonist), and DNQX (AMPA receptor antagonist), but not by K41498 (CRFR2 antagonist). These results indicate that stimulation of brain CRFR1 can be involved in facilitation of the rat micturition via brain NMDA/AMPA receptors.
Subject(s)
Receptors, Corticotropin-Releasing Hormone , Urination , Animals , Brain , Corticotropin-Releasing Hormone/pharmacology , Male , N-Methylaspartate/pharmacology , Rats , Rats, Wistar , Receptors, N-Methyl-D-AspartateABSTRACT
Reductive alkynylation of aldehydes by the Umpolung approach was developed using a photoredox catalyst under blue LED irradiation. Ketyl radicals, generated by single-electron reduction of aldehydes through proton-coupled electron transfer (PCET), reacted with electrophilic alkynylsulfones. Sterically demanding bulky aldehydes reacted smoothly under the Umpolung reaction conditions. Moreover, the alkynylation proceeded chemoselectively with an aryl aldehyde group in the presence of other carbonyl groups including an aliphatic aldehyde group.
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Brain nicotinic acetylcholine receptors (nAChRs) reportedly suppress the micturition, but the mechanisms responsible for this suppression remain unclear. We previously reported that intracerebroventricularly administered (±)-epibatidine (non-selective nAChR agonist) activated the sympatho-adrenomedullary system, which can affect the micturition. Therefore, we investigated (1) whether intracerebroventricularly administered (±)-epibatidine-induced effects on the micturition were dependent on the sympatho-adrenomedullary system, and (2) brain nAChR subtypes involved in the (±)-epibatidine-induced effects in urethane-anesthetized male Wistar rats. Plasma noradrenaline and adrenaline (catecholamines) were measured just before and 5 min after (±)-epibatidine administration. Evaluation of urodynamic parameters, intercontraction intervals (ICI) and maximal voiding pressure (MVP) by cystometry was started 1 h before (±)-epibatidine administration or intracerebroventricular pretreatment with other drugs and continued 1 h after (±)-epibatidine administration. Intracerebroventricularly administered (±)-epibatidine elevated plasma catecholamines and prolonged ICI without affecting MVP, and these changes were suppressed by intracerebroventricularly pretreated mecamylamine (non-selective nAChR antagonist). Acute bilateral adrenalectomy abolished the (±)-epibatidine-induced elevation of plasma catecholamines, but had no effect on the (±)-epibatidine-induced ICI prolongation. The latter was suppressed by intracerebroventricularly pretreated methyllycaconitine (selective α7-nAChR antagonist), SR95531 (GABAA antagonist), and SCH50911 (GABAB antagonist), but not by dihydro-ß-erythroidine (selective α4ß2-nAChR antagonist). Intracerebroventricularly administered PHA568487 (selective α7-nAChR agonist) prolonged ICI without affecting MVP, similar to (±)-epibatidine. These results suggest that stimulation of brain α7-nAChRs suppresses the rat micturition through brain GABAA/GABAB receptors, independently of the sympatho-adrenomedullary outflow modulation.
Subject(s)
Brain/metabolism , Receptors, GABA/metabolism , Urination , alpha7 Nicotinic Acetylcholine Receptor/metabolism , Adrenal Medulla/drug effects , Adrenal Medulla/metabolism , Adrenalectomy , Animals , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Epinephrine/blood , Male , Muscle Contraction/drug effects , Norepinephrine/blood , Pyridines/pharmacology , Rats, Wistar , Sympathetic Nervous System/drug effects , Sympathetic Nervous System/metabolismABSTRACT
The optimal method of the polymer Materials Informatics (MI) has not been developed because the amorphous nature of the higher-order structure affects these properties. We have now tried to develop the polymer MI's descriptor of the higher-order structure using persistent homology as the topological method. We have experimentally studied the influence of the MD simulation cell size as the higher-order structure of the polymer on its electrical properties important for a soft material sensor or actuator device. The all-atom MD simulation of the polymer has been calculated and the obtained atomic coordinate has been analyzed by the persistent homology. The change in the higher-order structure by different cell size simulations affects the dielectric constant, although these changes are not described by a radial distribution function (RDF). On the other hand, using the 2nd order persistent diagram (PD), it was found that when the cell size is small, the island-shaped distribution become smoother as the cell size increased. There is the same tendency for the condition of change in the monomer ratio, the polymer chain length or temperature. As a result, the persistent homology may express the higher-order structure generated by the MD simulation as a descriptor of the polymer MI.
ABSTRACT
AIM: Brain nitric oxide (NO) have been reported in regulation of the sympatho-adrenomedullary system, which can affect voiding and storage functions. Therefore, we investigated effects of intracerebroventricularly (icv) administered 3-(4-morpholinyl)sydnonimine, hydrochloride (SIN-1) (NO donor) on the micturition reflex, focusing on their dependence on the sympatho-adrenomedullary system and on brain N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors in urethane-anesthetized (0.8 g/kg, ip) male Wistar rats. METHODS: Plasma noradrenaline and adrenaline were measured just before and 5 minutes after SIN-1 administration. Evaluation of urodynamic parameters was started 1 hour before SIN-1 administration or intracerebroventricular pretreatment with other drugs. RESULTS: SIN-1 (100 and 250 µg/animal) elevated plasma adrenaline and reduced intercontraction interval ([ICI] values; 110.5% [SIN-1, 0 µg] and 54.9% [SIN-1, 250 µg] during 15 minutes after SIN-1 administration [P < .05; η2 = 0.59]) without affecting plasma noradrenaline or maximal voiding pressure. SIN-1 (250 µg/animal) reduced single-voided volume and bladder capacity without affecting post-voiding residual volume. The SIN-1 (250 µg/animal)-induced adrenaline elevation and ICI reduction were attenuated by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, sodium salt (carboxy-PTIO) (NO scavenger, icv) (ICI values; 44.7% [vehicle + SIN-1] and 77.5% [carboxy-PTIO + SIN-1] during 15 minutes after SIN-1 administration [P < .05; η2 = 0.51]). Acute bilateral adrenalectomy abolished SIN-1-induced adrenaline elevation, while showed no effect on the SIN-1-induced ICI reduction. The ICI reduction was attenuated by MK-801 (NMDA receptor antagonist, icv) (ICI values; 47.0% [vehicle + SIN-1] and 87.6% [MK-801 + SIN-1] during 15 minutes after SIN-1 administration [P < .05; η2 = 0.61]), but not by DNQX (AMPA receptor antagonist, icv). CONCLUSION: Brain NO is involved in facilitation of the rat micturition reflex through brain NMDA receptors, independently of the sympatho-adrenomedullary outflow modulation.
Subject(s)
Brain/drug effects , Nitric Oxide/metabolism , Receptors, AMPA/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Urination/drug effects , Animals , Brain/metabolism , Dizocilpine Maleate/pharmacology , Epinephrine/blood , Excitatory Amino Acid Antagonists/pharmacology , Male , Molsidomine/analogs & derivatives , Molsidomine/pharmacology , Nitric Oxide Donors/pharmacology , Norepinephrine/blood , Quinoxalines/pharmacology , Rats , Rats, Wistar , Reflex/drug effects , Reflex/physiology , Urination/physiologyABSTRACT
Chemoselective reactions can contribute to streamlining synthesis of pharmaceuticals, agrochemicals, and other functional molecules by avoiding use of protecting groups. In this review, copper catalysts were demonstrated useful for developing two types of chemoselective reactions: C-C bond-forming reactions at an anomeric carbon of unprotected aldoses and difunctionalization reaction of C-C multiple bonds. The "soft" nucleophilic copper species exhibit orthogonal reactivity toward "hard" polar functional groups and preferentially react with "soft" functional groups. The catalysis also controls stereoselectivity and/or regioselectivity to provide value-added products from readily available feedstock compounds.
Subject(s)
Biological Products/chemical synthesis , Copper/chemistry , Drug Development , Pharmaceutical Preparations/chemical synthesis , Biological Products/chemistry , Catalysis , Molecular Conformation , Pharmaceutical Preparations/chemistry , StereoisomerismABSTRACT
A chiral phenol-NHC ligand enabled the copper-catalyzed enantioselective conjugate reduction of α,ß-unsaturated esters. The phenol moiety of the chiral NHC ligand played a critical role in producing the enantiomerically enriched products. The catalyst worked well for various (Z)-isomer substrates. Opposite enantiomers were obtained from (Z)- and (E)-isomers, with a higher enantiomeric excess from the (Z)-isomer.
ABSTRACT
Anti-cancer chemotherapy with good efficacy and fewer side effects is highly desirable. A drug delivery system comprising a cancer-targeting module and a cytotoxic agent connected with a cleavable linker is promising for reducing side effects. The development of a cleavable linker satisfying the requirements of both stability and cleavability, however, is difficult, especially when a carbonate moiety is used for conjugating the linker to a hydroxy group in a drug of interest. We herein report a new stable linker comprising carbamate and ester spacers, which can be introduced on a hydroxy group of a drug. This linker is more stable in aqueous neutral buffer than a corresponding carbonate-type linker, and releases a payload anti-cancer drug, SN-38, through a two-step sequence upon cathepsin B treatment. This linker may have potential use in other drug delivery systems to lower side effects by selectively transporting cytotoxic drugs to tumor cells.
Subject(s)
Antineoplastic Agents/chemistry , Drug Carriers/chemistry , Oxygen/chemistry , Antineoplastic Agents/analysis , Antineoplastic Agents/metabolism , Carbamates/chemistry , Cathepsin B/metabolism , Cell Line, Tumor , Chromatography, High Pressure Liquid , Drug Liberation , Esters/chemistry , Humans , Irinotecan/analysis , Irinotecan/chemistry , Irinotecan/metabolismABSTRACT
Peptidoglycan is an indispensable component of bacterial cell walls. We recently discovered an alternative peptidoglycan biosynthetic pathway, which involves two enzymes, MurD2 and MurL, catalyzing the ligation of L-Glu to UDP-MurNAc-L-Ala and epimerization of the terminal L-Glu of the MurD2 product, respectively. Because the pathway operates in Xanthomonas oryze, a pathogen causing bacterial blight of rice, we searched for specific inhibitors from metabolites produced by actinomycetes to obtain a lead compound to function as an agrochemical. Actinomycin D was isolated from Streptomyces parvulus NBRC 13193 as a specific inhibitor of the pathway. In vitro analysis indicated that actinomycin D inhibited the MurD2 reaction.
Subject(s)
Anti-Bacterial Agents/pharmacology , Dactinomycin/pharmacology , Peptidoglycan/drug effects , Streptomyces/metabolism , Xanthomonas/drug effects , Anti-Bacterial Agents/isolation & purification , Dactinomycin/isolation & purification , Peptidoglycan/biosynthesis , Xanthomonas/enzymologyABSTRACT
In advanced cancer patients, malignant cells invade and disseminate within normal cells and develop resistance to therapy with additional genetic mutations, which makes radical cure very difficult. Precision medicine against advanced cancer is hampered by the lack of systems aimed at multiple target molecules within multiple loci. Here, we report the development of a versatile diagnostic and therapeutic system for advanced cancer, named the Cupid and Psyche system. Based on the strong non-covalent interaction of streptavidin and biotin, a low immunogenic mutated streptavidin, Cupid, and a modified artificial biotin, Psyche, have been designed. Cupid can be fused with various single-chain variable fragment antibodies and forms tetramer to recognize cancer cells precisely. Psyche can be conjugated to a wide range of diagnostic and therapeutic agents against malignant cells. The Cupid and Psyche system can be used in pre-targeting therapy as well as photo-immunotherapy effectively in animal models supporting the concept of a system for precision medicine for multiple targets within multiple loci.
Subject(s)
Antineoplastic Agents/chemistry , Biotin/chemistry , Neoplasms/diagnosis , Neoplasms/drug therapy , Streptavidin/chemistry , Animals , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Drug Delivery Systems , Humans , Immunotherapy , Precision Medicine , Single-Chain Antibodies/chemistryABSTRACT
A boron-catalyzed α-amination of simple carboxylic acids was developed. Catalytically generated boron enolates of carboxylic acids reacted with an electrophilic aminating reagent, diisopropylazodicarboxylate, to provide amino acid derivatives. The catalysis afforded not only α-monosubstituted glycine derivatives but also α,α-disubstituted derivatives. The resulting α-aminocarboxylic acid was easily converted to carboxylic acid derivatives. Extension to a catalytic asymmetric variant was possible by introducing a chiral ligand on the boron catalyst.
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Copper(I)-catalyzed stereodivergent nucleophilic propargylation at the anomeric carbon of unprotected N-acetyl mannosamine was developed using 3-substituted allenylboronates as a nucleophile. The homopropargylic alcohol products contained two contiguous stereocenters, and two stereoisomers out of the four possible isomers were selectively obtained in a catalyst-controlled manner by applying either basic conditions: a MesCu/(R,R,R)-Ph-SKP catalyst with a B(OiPr)3 additive or acidic conditions: a CuBF4/(S,S,S)-Ph-SKP catalyst with an MeB(OiPr)2 additive. Mechanistic studies suggested the presence of distinct active nucleophilic species depending on the conditions: an allenylcopper species under the basic conditions or an allenylboronate activated by the Lewis acidic copper catalyst under the acidic conditions. The propargylation products were concisely transformed into C3-substituted sialic acids in two steps without the use of protecting groups.