Enantioselective Radical Addition/Trapping Reactions with α,β-Disubstituted Unsaturated Imides. Synthesis of anti-Propionate Aldols
摘要:
This manuscript describes a highly diastereo- and enantioselective intermolecular radical addition/hydrogen atom transfer to alpha,beta-disubstituted enoates. Additionally, we show that anti-propionate aldol-like products can be easily prepared from alpha-methyl-beta-acyloxyenoates in good yields and high diastereo- and enantioselectivities.
2-Vinylcyclobutanones by Cycloaddition of Vinylketenes to Simple Olefins
作者:David A. Jackson、Max Rey、Andr� S. Dreiding
DOI:10.1002/hlca.19830660744
日期:1983.11.2
methods were compared, all involving in situ generation of the ketenes 2 by HCl-elimination from α,β-unsaturated acid chlorides 1; the most effective employed a large excess of olefin 3 and a high reaction temperature. The [2+2]-cycloadditions were fully regio- and stereoselective with respect to the olefin 3, but less so with respect to the ketene 2, so that - where possible - two stereoisomers of
Preparation of 2-vinylcyclobutanones and their conversion to cyclopentenones
作者:David A. Jackson、Max Rey、André S. Dreiding
DOI:10.1016/s0040-4039(00)94015-2
日期:1983.1
Methyl- and ethyl-vinylketene were added to several simple olefins to afford alkylated 2-vinylcyclobutanones , which in turn rearranged to cyclopentenones (via dienones ,) or (via 1,2-acyl migration) under acid catalysis. Evidence is presented for a cyclopropyl-carbinyl intermediate .
[EN] BICYCLO[3.3.1]NONANES AND BICYCLO[3.3.1]NONENES AND THEIR USE AS FLAVOUR OR FRAGRANCE INGREDIENT<br/>[FR] BICYCLO[3.3.1]NONANES ET BICYCLO[3.3.1]NONENES ET LEUR UTILISATION EN TANT QU'INGREDIENT DE SAVEUR OU D'AROME
申请人:GIVAUDAN SA
公开号:WO2005070860A1
公开(公告)日:2005-08-04
The present invention relates to substituted bicyclo[3.3.1]nonanes and bicyclo[3.3.1]nonenes of formula (I) wherein R, and R1 to R5 have the same meaning as described in the specification.
Bicyclo(3.3.1)Nonanes and Bicyclo(3.3.1)Nonenes and Their Use as Flavor or Fragrance Ingredient
申请人:Granier Thierry
公开号:US20080274927A1
公开(公告)日:2008-11-06
The present invention relates to substituted bicyclo[3.3.1]nonanes and bicyclo[3.3.1]nonenes of formula (I)
wherein R, and R
1
to R
5
have the same meaning as described in the specification.
Enantioselective Synthesis of α,β-Disubstituted-β-amino Acids
作者:Mukund P. Sibi、Prabagaran Narayanasamy、Sandeep G. Ghorpade、Craig P. Jasperse
DOI:10.1021/ja0372309
日期:2003.10.1
Highly diastereoselective and enantioselective addition of N-benzylhydroxylamine to imides 17 and 20-30 produces alpha,beta-trans-disubstituted N-benzylisoxazolidinones 19 and 31-41. These reactions proceed in 60-96% ee with 93-99% de's using 5 mol % of Mg(NTf2)2 and ligand 18. The product isoxazolidinones can be hydrogenolyzed directly to provide alpha,beta-disubstituted-beta-amino acids.