Organo-catalyzed enantioselective synthesis of some β-silyl γ-alkyl γ-butyrolactones as intermediates for natural products
摘要:
The enantioselective synthesis of some beta-silyl gamma-alkyl gamma-butyrolactones has been achieved by an organo-catalyzed Michael addition of enolizable aldehydes onto a silylmethylene malonate followed by a silicon-facilitated Bayer-Villiger oxidation of the beta-silyl aldehyde adducts as the key step. gamma-Alkyl gamma-butenolides were obtained from the beta-silyl gamma-alkyl gamma-butyrolactones by Fleming-Tamao oxidation of the silyl group to a hydroxy group and subsequent elimination. These butenolides are the advanced intermediates of some natural products such as (+)-gamma-caprolactone, (+)-methylenolactocine, and (-)-quercus lactone. (C) 2011 Elsevier Ltd. All rights reserved.
Organo-catalyzed enantioselective synthesis of some β-silyl γ-alkyl γ-butyrolactones as intermediates for natural products
摘要:
The enantioselective synthesis of some beta-silyl gamma-alkyl gamma-butyrolactones has been achieved by an organo-catalyzed Michael addition of enolizable aldehydes onto a silylmethylene malonate followed by a silicon-facilitated Bayer-Villiger oxidation of the beta-silyl aldehyde adducts as the key step. gamma-Alkyl gamma-butenolides were obtained from the beta-silyl gamma-alkyl gamma-butyrolactones by Fleming-Tamao oxidation of the silyl group to a hydroxy group and subsequent elimination. These butenolides are the advanced intermediates of some natural products such as (+)-gamma-caprolactone, (+)-methylenolactocine, and (-)-quercus lactone. (C) 2011 Elsevier Ltd. All rights reserved.
Stereoselective Synthesis of Polysubstituted Tetrahydropyranones via Acid-Promoted Cyclization of β-Silyl-γ-ethylidene-γ-butyrolactones with Aldehydes and Ketones
β-Silyl-γ-ethylidene-γ-butyrolactone upon one-pot treatment with aldehydes and ketones in the presence of Lewis acids underwent a tandem Hosomi–Sakurai/Prins cyclization to give polysubstituted tetrahydropyranones stereoselectively. Various aldehydes and ketones can be used in this reaction to produce the corresponding tetrahydropyranones. The optical purity of the starting γ-butyrolactone was substantially
NHC–Cu(i) catalysed asymmetric conjugate silyl transfer to unsaturated lactones: application in kinetic resolution
作者:Vittorio Pace、James P. Rae、Hassan Y. Harb、David J. Procter
DOI:10.1039/c3cc42160k
日期:——
The scope of the asymmetric silyl transfer to unsaturated lactones utilising a C2-symmetric NHCâCu(I) catalyst has been established and kinetic resolutions mediated by silyl transfer have been used to prepare enantiomerically enriched anti-4,5-disubstituted 5-membered lactones. The method has been exploited in an expedient synthesis of (+)-blastmycinone.
Organo-catalyzed enantioselective synthesis of some β-silyl γ-alkyl γ-butyrolactones as intermediates for natural products
作者:Raghunath Chowdhury、Sunil K. Ghosh
DOI:10.1016/j.tetasy.2011.10.013
日期:2011.11
The enantioselective synthesis of some beta-silyl gamma-alkyl gamma-butyrolactones has been achieved by an organo-catalyzed Michael addition of enolizable aldehydes onto a silylmethylene malonate followed by a silicon-facilitated Bayer-Villiger oxidation of the beta-silyl aldehyde adducts as the key step. gamma-Alkyl gamma-butenolides were obtained from the beta-silyl gamma-alkyl gamma-butyrolactones by Fleming-Tamao oxidation of the silyl group to a hydroxy group and subsequent elimination. These butenolides are the advanced intermediates of some natural products such as (+)-gamma-caprolactone, (+)-methylenolactocine, and (-)-quercus lactone. (C) 2011 Elsevier Ltd. All rights reserved.