Asymmetric Michael Addition of Malonates to Enones Catalyzed by a Primary β-Amino Acid and Its Lithium Salt
作者:Masanori Yoshida、Mao Narita、Shoji Hara
DOI:10.1021/jo201429w
日期:2011.10.21
Highly enantioselective Michaeladdition of malonates to enones was achieved using a mixed catalyst consisting of a primary β-amino acid, O-TBDPS (S)-β-homoserine, and its lithium salt. Various cyclic and acyclic enones were converted into 1,5-ketoesters in high yields (up to 92%) with high enantioselectivity (up to 97% ee) under mild reaction conditions. Details of synthesis of the catalyst, optimization
Asymmetric organocatalytic conjugate addition of malonates to enones using a proline tetrazole catalyst
作者:Kristian Rahbek Knudsen、Claire E. T. Mitchell、Steven V. Ley
DOI:10.1039/b514636d
日期:——
5-Pyrrolidin-2-yltetrazole performs as a useful organocatalyst for the asymmetric addition of malonates to a range of enones, with good to excellent enantioselectivities.
A New Microwave-Assisted Organocatalytic Solvent-Free Synthesis of Optically Enriched Michael Adducts
作者:Antonio Procopio、Antonio De Nino、Monica Nardi、Manuela Oliverio、Rossella Paonessa、Raffaele Pasceri
DOI:10.1055/s-0030-1258126
日期:2010.7
A high-yielding reaction protocol for the microwave-assisted organocatalytic conjugate addition of diethyl malonate to enones under solvent-free conditions is proposed. The method still permits the use of cheap and commercially available L -proline furnishing very good performance at least in the case of 1-alkyl-3-monosubstituted enones.
A General Organocatalytic Enantioselective Malonate Addition to α,β-Unsaturated Enones
作者:Veit Wascholowski、Kristian Rahbek Knudsen、Claire E. T. Mitchell、Steven V. Ley
DOI:10.1002/chem.200800673
日期:2008.7.7
A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to alpha,beta-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic enones can be used and the reaction with ethyl malonates 3 b provides the Michaeladdition products in high yields with good to excellent enantioselectivities
Organocatalytic Enantioselective Conjugate Additions to Enones
作者:Jian Wang、Hao Li、Liansuo Zu、Wei Jiang、Hexin Xie、Wenhu Duan、Wei Wang
DOI:10.1021/ja065187u
日期:2006.10.1
Conjugateaddition reactions of a wide range of nucleophilic enol species with enones, catalyzed by a cinchona alkaloid derived thiourea organocatalyst, have been developed with attending good yields and high enantioselectivities under a mild reaction condition. The general method provides an efficient approach to the preparation of versatile building blocks possessing various functional groups.