A highly efficient asymmetric synthesis of β-aminophosphonic acids, via addition of α-phosphonate carbanions to chiral, enantiopure sulfinimines
摘要:
Addition of alpha-phosphonate carbanions to (S)-sulfinimines 1 affords N-sulfinyl beta-aminophosphonates 2 in a diastereoisomeric ratio from 5:1 to 10:1; the major diastereoisomers of 2, after separation, are converted to the corresponding beta-aminophosphonates 3 or to (+)-beta-amino-beta-phenylethane phosphonic acid 4, whose absolute configuration was established as (R) by X-ray crystallography.
Asymmetric Aza-Henry Reactions from <i>N</i>-<i>p</i>-Tolylsulfinylimines
作者:José Luis García Ruano、Markus Topp、Jesús López-Cantarero、José Alemán、Modesto J. Remuiñán、M. Belén Cid
DOI:10.1021/ol051580d
日期:2005.9.1
[reaction: see text] N-Sulfinylimines derived from aromatic or aliphatic aldehydes and ketones react with nitromethane and NaOH in a highly diastereoselective manner under mild conditions. In the presence of TBAF, the reaction rates are strongly increased and the stereoselectivity is inverted. This method provides enantiomerically pure beta-nitroamines derived from enolizable aldimines and ketimines
Preparation of α-amino ketones, β-amino hydroxylamines using asymmetric aza-Henry reactions of N-p-tolylsulfinylimines with nitroethane
作者:José Luis García Ruano、Jesús López-Cantarero、Teresa de Haro、José Alemán、M. Belén Cid
DOI:10.1016/j.tet.2006.10.021
日期:2006.12
N-Sulfinylimines derived from aromatic and aliphatic aldehydes react with nitroethane and NaOH, yielding mainly two diastereoisomeric β-nitroamines as the result of a highly diastereoselective reaction and further epimerization of the carbon linked to the nitro group. The resulting β-nitroamines are used as precursors of N-sulfonyl α-amino methyl ketones and β-amino hydroxylamines.