Enantioselective 1,4-Addition Reactions of Diphenyl Phosphite to Nitroalkenes Catalyzed by an Axially Chiral Guanidine
作者:Masahiro Terada、Takashi Ikehara、Hitoshi Ube
DOI:10.1021/ja0746619
日期:2007.11.1
A highlyenantioselective 1,4-addition reaction of nitroalkenes with diphenyl phosphite was successfully accomplished using a newly developed axiallychiral guainidine catalyst. A broad range of nitroalkenes, bearing not only aromatic but also aliphatic substituents, is applicable to the present enantioselectivereaction. The method provides an efficient protocol to synthesize enantioenriched β-amino
phospha-Michael reaction of diphenyl phosphonate to nitroolefins was achieved by utilizing a 1,3-diamine-tethered guanidinium/bisthioureaorganocatalyst. The procedure is applicable to nitroolefins having various aromatic and aliphatic substituents, and enables an efficient access to phospha-Michael products with 90–98% ee. Monomeric or oligomeric active species of the catalyst can be utilized, depending
Quinidine thiourea-catalyzed enantioselective synthesis of β-nitrophosphonates: beneficial effects of molecular sieves
作者:Santhi Abbaraju、Mayur Bhanushali、Cong-Gui Zhao
DOI:10.1016/j.tet.2011.07.059
日期:2011.9
An efficient method for enantioselective synthesis of beta-nitrophosphonates via the Michael addition of diphenyl phosphite to nitroalkenes using the readily available quinidine thiourea organocatalyst has been developed. The desired beta-nitrophosphonates were obtained in good ee values. Molecular sieves were found to be crucial for achieving high reproducible yields in this reaction. (C) 2011 Elsevier Ltd. All rights reserved.