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Updated: Jul 16, 2026

Synthesis of High Purity Nonsymmetric Dialkylphosphinic Acid Extractants
Published on: October 19, 2017
Opening of tartrate acetals using dialkylboron bromide: evidence for stereoselectivity downstream from ring fission
Yvan Guindon1, William W Ogilvie, Josée Bordeleau
1Boehringer Ingelheim (Canada) Ltd., Bio-Méga Research Division, 2100 rue Cunard, Laval Québec, Canada H7S 2G5.
Abstract:
Johnson-type acetals derived from dimethyl tartrate give, after opening with Me(2)BBr and cuprate displacement, secondary alcohols with high diastereoselectivity (>30:1). The mechanism proposed for the induction of diastereoselectivity is downstream from the ring fission. It implies a direct participation of the Lewis acid as a source of nucleophile and the stereospecific transformation of the resulting bromo acetal through an invertive and temperature-dependent process. The acetals are prepared by reaction of the desired aldehyde with dimethyl tartrate. Removal of the auxiliary is accomplished through SmI(2) reduction or by an addition-elimination protocol using methoxide.
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