D-Glucosamine was successfully employed as a chiral auxiliary for the enantioselective synthesis of phosphineoxides. The influence of the anomeric position was also investigated and revealed the excellent ability of the α-anomer to perform this transformation in a highly selective fashion. The methodology employed consisted of three steps: diastereoselective formation of the oxazaphospholidine followed
3) enantioselective synthesis of phosphineoxides by cleavage of the remaining PO bond. Interestingly, the use of a PIII phosphine precursor afforded a P‐epimer oxazaphospholidine. Hence, the two enantiomeric phosphineoxides can be synthesized starting from either a PV or a PIII phosphine precursor, which constitutes a clear advantage for the stereoselectivesynthesis of sterically hindered phosphineoxides.
Two-Step Substitution Reaction of Phosphonates Carrying a Binaphthyl Group with Grignard Reagents Leading to the Formation of P-Chirogenic Phosphine Oxides
P-chirogenic tertiary phosphine oxides with a high enantiomeric ratio. Rare examples of P-chirogenic alkynyl phosphine oxides were also obtained. The sequential one-pot substitution reaction of phosphonates bearing a binaphthyl group with two different Grignardreagents successfully gave the corresponding P-chirogenic phosphine oxides with enantiomeric ratios nearly equal to those of oxides derived from two-step
A Novel Resolution Procedure for the Preparation of P-Stereogenic Phosphine Oxides
作者:Neil G. Andersen、Philip D. Ramsden、Daqing Che、Masood Parvez、Brian A. Keay
DOI:10.1021/ol991174s
日期:1999.12.1
[GRAPHICS]A new general route for preparing enantiomerically pure P-stereogenic phosphine oxides has been developed by exploiting the Staudinger reaction between racemic tertiary phosphines and an enantiomerically pure organoazide. The resulting phosphinimines are easily resolved by either crystallization or flash chromatography and serve as synthetic intermediates toward enantiomerically pure phosphine oxides.
Kielbasinski; Zurawinski; Pietrusiewicz, Polish Journal of Chemistry, 1998, vol. 72, # 3, p. 564 - 572