Catalytic enantioselective direct Michael additions of ketones to alkylidene malonates
作者:Juan M Betancort、Kandasamy Sakthivel、Rajeswari Thayumanavan、Carlos F Barbas
DOI:10.1016/s0040-4039(01)00793-6
日期:2001.7
Enantioselective direct Michaeladditions of ketones using (S)-1-(2-pyrrolidinylmethyl)-pyrrolidine as a catalyst are described. Michael adducts with up to 91% e.e. were obtained by the reaction of alkylidenemalonates with simple unactivated ketones under mild reaction conditions.
An organocatalytic asymmetric Michaeladdition of ketones to alkylidenemalonates has been developed. In the presence of 20 mol % of urea 1a or N-(pyrrolidin-2-ylmethyl)trifluoromethanesulfonamide 1j, the reactions of ketones with alkylidenemalonates afford the desired Michael adducts in moderate to good yields with good to high enantioselectivities under mild conditions.
Solvent free, fast and asymmetric Michael additions of ketones to nitroolefins using chiral pyrrolidine–pyridone conjugate bases as organocatalysts
作者:Chandan K. Mahato、Mrinalkanti Kundu、Animesh Pramanik
DOI:10.1016/j.tetasy.2017.03.002
日期:2017.4
New chiral organocatalysts are envisaged based on a pyrrolidine-pyridone conjugate and synthesized from commercially available proline employing standard protocols. These catalysts were found to be useful for asymmetric Michael additions of ketones to nitroolefins to afford the desired products in very good yields (up to 98%) with excellent diastereo- and enantioselectivities (>97:3 syn/anti and up to 98% ee) in very short reaction time compared with the existing reports. (C) 2017 Elsevier Ltd. All rights reserved.
Betancort, Juan M.; Sakthivel, Kandasamy; Thayumanavan, Rajeswari, Synthesis, 2004, # 9, p. 1509 - 1521
作者:Betancort, Juan M.、Sakthivel, Kandasamy、Thayumanavan, Rajeswari、Tanaka, Fujie、Barbas III, Carlos F.
DOI:——
日期:——
Blarer, Stefan J.; Seebach, Dieter, Chemische Berichte, 1983, vol. 116, # 6, p. 2250 - 2260