Hoffmann-La Roche Inc.

Donald E Berger, Jr

Milan R Uskokovic

Andrew D Batcho

The present disclosure is directed to a process and intermediates for the synthesis of Vitamin D.sub.3 metabolites such as 1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol and 24R,25-dihydroxycholecalciferol from 17-keto steroids via intermediates having the natural steroid configuration at the 20-position. These novel intermediates are prepared from 17-keto steroids by reaction with ethyltriphenylphosphonium halides followed by reaction with formaldehyde to form comounds having the natural steroid configuration at the 20-position and which are suitable substrates for the preparation of the aforementioned Vitamin D.sub.3 metabolites.

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Mountain View, CA, United States of America

Donald E Berger, Jr