Zhaohui Qu

Bio: Zhaohui Qu is an academic researcher from Peking University. The author has contributed to research in topics: Diazo & Lewis acids and bases. The author has an hindex of 8, co-authored 15 publications receiving 280 citations.

Catalytic asymmetric [2,3]-sigmatropic rearrangement of sulfur ylides generated from copper(I) carbenoids and allyl sulfides.

Abstract: Catalytic asymmetric sulfur ylide [2,3]-sigmatropic rearrangement of carbenoids generated from aryldiazoacetates has been investigated with a number of chiral Rh(II) and Cu(I) catalysts, and moderately high enantioselectivity (52−78% ee) can be achieved with Cu(MeCN)4PF6/2,2‘-isopropylidenebis[(4S)-4-tert-butyl-2-oxazoline].

Investigation of the Transition-Metal- and Acid-Catalyzed Reactions of β-(N-Tosyl)amino Diazo Carbonyl Compounds

Abstract: A series of β-(N-tosyl)amino diazo carbonyl compounds have been prepared by nucleophilic condensation of N-tosylimines with acyldiazomethanes. The diazo decomposition of these diazo carbonyl compounds under various catalytic conditions, including Rh(II) carboxylates, Cu(I) and Cu(II) complexes, PhCO2Ag/Et3N, TsOH, and SnCl2·2H2O, has been investigated. It was found that, in most cases, the diazo decomposition gave preferentially 1,2-aryl migration product, but 1,2-hydride migration predominated when PhCO2Ag/Et3N was the catalytic system. Hammett correlation has been applied in the analysis of the electronic effects of 1,2-aryl migration. The factors that govern the migratory preference and the mechanistic aspects of the reaction are discussed.

A Kinetic Study on the Pairwise Competition Reaction of α-Diazo Esters with Rhodium(II) Catalysts: Implication for the Mechanism of Rh(II)-Carbene Transfer

Abstract: The relative rate constants for the Rh(II)-mediated diazo decomposition of a series of para- or meta-substituted diazophenylacetates were measured through intermolecular competition. The kinetic data were further subjected to Hammett correlation analysis and were found to have better linear correlation with σ+. Reaction constants for four Rh(II) catalysts have been obtained, Rh2(OAc)4 (ρ = −1.29 with σ+, r = −0.99), Rh2(Ooct)4 (ρ = −1.31 with σ+, r = −0.99), Rh2(acam)4 (ρ = −1.18 with σ+, r = −0.99), Rh2(O2CCF3)4 (ρ = −1.46 with σ+, r = −0.99). The mechanistic implications of these data are discussed.

Lewis Acid Controlled Regioselective 1,2 and 1,4 Reaction of α,β‐Unsaturated Carbonyl Compounds with TiIV Enolates Derived from α‐Diazo β‐Keto Carbonyl Compounds

Abstract: The addition of nucleophiles to , -unsaturated carbonyl compounds is a fundamental transformation in organic synthesis. Since there are two reaction sites in the , -unsaturated carbonyl functional group, this addition reaction can only be of practical synthetic utility in organic synthesis if one seems particularly appealing for large-scale operations and for different substrates; with the emergence of a considerable number of new RTILs,[3, 11] it should be possible to design RTILs with high selectivity for specific substrates. The possibility of using nonpolar solvents with high boiling points or water instead of diethyl ether, and supported RTIL in hollow-fiber membranes will allow this technology to reinforce its environmentally benign character and become attractive for industrial application.

Linear Free Energy Correlation Analysis on the Electronic Effects of Rh(II) Carbene O−H Insertion

Abstract: The relative rate constants for the Rh(II)-catalyzed insertion of diazoacetone into the O-H bond have been measured through intermolecular competitions. The kinetic data were subjected to Hammett correlation analysis, and mechanistic implication of the results with respect to a stepwise vs a concerted O-H insertion pathway is discussed.