Rapid formation of Csp^(3)–Csp^(3) bonds through copper-catalyzed decarboxylative Csp^(3)–H functionalization

Transition-metal-catalyzed decarboxylative and C–H functionalization strategy for the construction of Csp^(2)-Csp^(2),Csp^(2)-Csp,and Csp^(2)-Csp^(3) bonds has been extensively studied.However,research surveys of this synthetic strategy for the Csp^(3)-Csp^(3) bond forming reactions are surprisingly scarce.Herein,we present an efficient approach for the rapid formation of Csp^(3)–Csp^(3) bond through copper-catalyzed decarboxylative Csp^(3)–H functionalization.The present method should provide a useful access to C3-substituted indole scaffolds with possible biological activities.Mechanistic experiments and DFT calculations supported a dual-Cu(Ⅱ)-catalytic cycle involving rate-determining decarboxylation in an outer-sphere radical pathway and spin-crossover-promoted C–C bond formation.This strategy offers a promising synthesis method for the construction of Csp^(3)–Csp^(3) bond in the field of synthetic and pharmaceutical chemistry and extends the number of still limited copper-catalyzed decarboxylative Csp^(3)–Csp^(3) bond forming reaction.

Targeted metabolomics study of fatty-acid metabolism in lean metabolic-associated fatty liver disease patients

BACKGROUND The annual incidence of metabolic-associated fatty liver disease(MAFLD)in China has been increasing and is often overlooked owing to its insidious charac-teristics.Approximately 50%of the patients have a normal weight or are not obese.They are said to have lean-type MAFLD,and few studies of such patients are available.Because MAFLD is associated with abnormal lipid metabolism,lipid-targeted metabolomics was used in this study to provide experimental evidence for early diagnosis and pathogenesis.MAFLD and analyze metabolic pathways.UPLC-Q-Orbitrap/MS content determination was used to determine serum palmitic acid(PA),oleic acid(OA),linoleic acid(LA),and arachidonic acid(AA)levels in lean-type MAFLD patients.RESULTS Urea nitrogen and uric acid levels were higher in lean-type MAFLD patients than in healthy individuals(P<0.05).Alanine transaminase and cholinesterase levels were higher in lean-type MAFLD patients than in healthy indi-viduals(P<0.01).The expression of high-density lipoprotein and apolipoprotein A-1 were lower in lean-type MAFLD patients than in healthy individuals(P<0.05)and the expression of triglycerides and fasting blood glucose were increased(P<0.01).A total of 65 biomarkers that affected the synthesis and metabolism of fatty acids were found with P<0.05 and variable importance in projection>1.The levels of PA,OA,LA,and AA were significantly increased compared with healthy individuals.CONCLUSION The metabolic profiles of lean-type MAFLD patients and healthy participants differed significantly,yielding 65 identified biomarkers.PA,OA,LA,and AA exhibited the most significant changes,offering valuable clinical guidance for prevention and treatment of lean-type MAFLD.

Visible-light-induced regioselective cross-dehydrogenative coupling of 2-isothiocyanatonaphthalenes with amines using molecular oxygen

An efficient and eco-friendly protocol for the construction of naphtho[2,1-d]thiazol-2-amines through visible-light photoredox-catalyzed C(sp2)–H/S–H cross-dehydrogenative coupling reactions between 2-isothiocyanatonaphthalenes and amines was established.In this reaction,the new C–N and C–S bonds are formed simultaneously in a single step.This new method provides a straightforward approach for constructing valuable sulfur-containing compounds.

Advances in theoretical study on transition-metal-catalyzed C-H activation

Transition-metal-catalyzed C–H activation represents one of most attractive research fields in modern organic chemistry while theoretical studies have become a popular and effective tool for elucidating mechanism nowadays. The recent achievements in the cross field of the two orientations are reviewed in this article. The first part introduced the advances in theoretical study on transition-metal-catalyzed C–H activation. The elegant work reported mainly in and after 2013, classified according to the mechanisms of C–H activation, were covered. The second part provided an analysis on the distribution of quantum-chemical methods, solvation models and basis sets in the collected theoretical studies.

Rh(Ⅰ)-catalyzed borylation of primary alkyl chlorides

Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh（I）-catalyzed cross-coupling of aliphatic electrophiles.

A self-catalytic role of methanol in PNP-Ru pincer complex catalysed dehydrogenation

Extracting hydrogen from methanol is a safe and cost-efficient strategy for fuel supply. This process was realized recently at a mild condition with excellent efficiency by ruthenium pincer catalysts. Despite the experimental success, the associated mechanism remains under debate. With the aid of density functional theory(DFT) calculations, an updated and self-consistent mechanism which involves Me OH-catalysed dehydrogenation of ruthenium hydride intermediate and pre-protonation of the pincer ligand was present herein. This mechanism is kinetically favoured over the previously-proposed water- or formic- acid-participated ones and more consistent with the optimal experimental condition where strong base and neat methanol solvent are used.

Mechanistic study on the regioselectivity of Co-catalyzed hydroacylation of 1,3-dienes

Density functional theory（DFT） method was used to explore the origin of the regioselectivity of Cocatalyzed hydroacylation of 1,3-dienes.The reaction of 2-methyl-1,3-butadiene and benzaldehyde with1,3-bis（diphenylphosphino）propane ligand was chosen as the model reaction.The energies of the intermediates and transition states in the stages of oxidative cyclization,β-H elimination and C-H reductive elimination were investigated.Computational results show that β-H elimination is the ratedetermining step for the whole catalytic cycle.C1-Selective oxidative cyclization is favored over C4-selective oxidative cyclization.Besides.C4-selective oxidative cyclization is kinetically disfavored than all the steps in C1-hydroacylation mechanisms,consistent with the experimentally obtained C1-selective hydroacylation products.Analyzing the reason for such observation,we suggest that both electronic and steric effects contribute to the C1-selectivity.On the electronic aspect,C1 is more electron rich than C4 due to the methyl group on C2,which makes the electrophilic attack of aldehyde carbon on C1 more favorable.On the steric aspect,the methyl group locates farther from the ligands in the transition state of C1-selective oxidative cyclization than in that of C4-selective oxidative cyclization.