Vitamin D₃ Synthetic Studies. A Three-Step Procedure for the Preparation of (+)-(1R,5R,6R,9R,2′R)-1-Methyl-9-(6-methylhept-2-yl)-5-(phenylsulfonyl)bicyclo[4.3.0]nonane from Windaus-Grundmann Ketone

Abstract

A procedure is described for the preparation of vitamin D₃ key fragment (+)-(1R,5R,6R,9R,2′R)-1-methyl-9-(6-methylhept-2-yl)-5-(phenylsulfonyl)bicyclo[4.3.0]nonane 3 in three steps and 55% overall yield from Windaus-Grundmann ketone 5.