A Highly<i>anti</i>-Selective Asymmetric Henry Reaction Catalyzed by a Chiral Copper Complex: Applications to the Syntheses of (+)-Spisulosine and a Pyrroloisoquinoline Derivative
作者:Kun Xu、Guoyin Lai、Zhenggen Zha、Susu Pan、Huanwen Chen、Zhiyong Wang
DOI:10.1002/chem.201201775
日期:2012.9.24
A highly anti‐selective asymmetricHenryreaction has been developed, affording synthetically versatile β‐nitroalcohols in a predominately anti‐selective manner (mostly above 15:1) and excellent ee values (mostly above 95 %). Moreover, the anti‐selective Henryreaction was carried out in the presence of water for the first time with up to 99 % ee. The catalytic mechanism was proposed based on the detection
A Highly syn-Selective Nitroaldol Reaction Catalyzed by CuII-Bisimidazoline
作者:Liang Cheng、Jiaxing Dong、Jingsong You、Ge Gao、Jingbo Lan
DOI:10.1002/chem.201000650
日期:——
Catalyzing Henry: Chiral bisimidazoline 1–Cu(OTf)2, in the presence of N‐methylmorpholine as a base, was discovered to efficiently catalyze the nitroaldolreaction in a highly syn‐ and enantioselective manner for a broad range of aldehydes, including aromatic, heteroaromatic, α,β‐unsaturated, and aliphatic aldehydes (see scheme).
An efficient one-pot protocol for the synthesis of (E)-nitroalkenes by reaction of aldehydes and nitroalkanes in the presence of polymer-bound triphenylphosphine, iodine and imidazole is described. Although the reaction works with similar efficiency with triphenylphosphine and its polymer-bound version, easy removal of the unwanted polymer-bound triphenylphosphine oxide and its recovery as triphenylphosphine provide the edge for practical application of the method. (C) 2013 Elsevier Ltd. All rights reserved.
A Heterobimetallic Pd/La/Schiff Base Complex foranti-Selective Catalytic Asymmetric Nitroaldol Reactions and Applications to Short Syntheses of β-Adrenoceptor Agonists