Addition of optically pure H-phosphinate to ketones: selectivity, stereochemistry and mechanism

作者:Sun Yong Ming; Xin Nana; Xu Zhong Yuan; Liu Li Juan; Meng Fan Jie; Zhang He; Fu Bao Ci; Liang Qiu Ju; Zheng Hong Xing; Sun Li Jun; Zhao Chang Qiu*; Han Li Biao
来源:Organic and Biomolecular Chemistry, 2014, 12(46): 9457-9465.
DOI:10.1039/c4ob01574f

摘要

Aromatic methyl ketones and cyclic asymmetric ketones underwent hydrophosphorylation with P-stereogenic H-P species in the presence of potassium carbonate to produce P,C-stereogenic tertiary alpha-hydroxyl phosphinates in excellent yields with up to 99 : 1 dr. The diastereoselectivity was induced by a reversible conversion of less stable stereomer of product to that of a more stable one via an equilibrium, which was confirmed by aldehyde/ketone exchanging reaction. Toward the exchange, aliphatic or aldehyde carbonyl were more active than aromatic or ketone carbonyls, respectively. The stability difference between the two diastereomers was controlled by the sizes of substituents linking to phosphorus or alpha-carbon.