We have successfully developed a strategy for the first time for the enantioselective Rh-TaniaPhos catalyzed asymmetric hydrogenation of unprotected β-enamine phosphonates to free β-amino phosphonates directly with good enantioselectivities (80%–86% ee) and high conversions (>99% conversion). The resulting chiral free β-amino phosphonates and their derivatives are important intermediates in biochemistry
as a catalyst. This method was used to obtain a series of chiral α-sulfonyl-β-aminophosphonates in yields of up to 96% with 89:11 dr and 88% ee. These compounds were further transformed into β-aminophosphonates or chiral azetidines with various functional groups by a Horner–Wadsworth–Emmons/aza-Michael addition reaction sequence.
A Facile Synthesis of Optically Active ?-Amino-?-arylethylphosphonates by Mitsunobu Reaction
作者:Chengfu Xu、Chengye Yuan
DOI:10.1002/ejoc.200400420
日期:2004.11
We describe a convenient and simple synthesis of opticallyactive β -amino-β-arylethylphosphonates based on Mitsunobe reactions of chiral β-aryl-β-hydroxyethylphosphonates, prepared in turn by Candida rugosa lipase catayzed kinetic resolution of the corresponding racemates.