Thiourea catalysed reduction of α-keto substituted acrylate compounds using Hantzsch ester as a reducing agent in water
作者:Guanglin Weng、Xiaobo Ma、Dongmei Fang、Ping Tan、Lijiao Wang、Linlin Yang、Yuanyuan Zhang、Shan Qian、Zhouyu Wang
DOI:10.1039/c7ra00995j
日期:——
The first method for the reduction of α-keto substituted acrylate compounds by Hantzsch ester in water under the catalysis of thiourea has been developed. The products were isolated in moderate to high yields (38–95%). These products are important intermediates in the synthesis of a series of natural products and other biologically active molecules.
Catalytic Asymmetric Insertion of Diazoesters into Aryl-CHO Bonds: Highly Enantioselective Construction of Chiral All-Carbon Quaternary Centers
作者:Lizhu Gao、Byung Chul Kang、Do Hyun Ryu
DOI:10.1021/ja408196g
日期:2013.10.2
This paper describes a catalytic enantioselective route to synthesize functionalized all-carbonquaternary acyclic systems via a boron Lewis acid-promoted formal C-C insertion of diazoesters into aryl-CHO bonds. In the presence of chiral (S)-oxazaborolidinium cation 1d as a catalyst, the reaction proceeded in good yield (up to 83%) with good regioselectivity (up to 88:12) and excellent enantioselectivity
The firstcatalytic enantioselective Roskamp reaction of alpha-alkyl-alpha-diazoesters with aromaticaldehydes was realized using a simple chiral N,N'-dioxide-scandium(III) complex. Remarkably, with 0.05 mol % catalyst, the reaction was performed well over a series of substrates, giving the desired products chemoselectively in excellent yields (up to 99%) and enantioselectivities (up to 98% ee) under