A general method for the synthesis of 3,5-cyclovitamin D3 and derivatives. A stereoselective synthesis of vitamin D3

Abstract

A stereoselective synthesis of vitamin D₃(1) was achieved via 3,5-cyclovitamin D₃(33) which was synthesized from the chiral aldehyde (3) and the vinyl bromide (27) derived from Grundmann's ketone (25). (±)-(Z)-5-(2-Cyclohexylidene-ethylidene)-4-methylenecyclohexane-r-1, t-3-diol (24) as a model compound of 1α-hydroxyvitamin D₃ was also stereoselectively synthesized via the solvolysis of (±)-α-cyclohexylidenemethyl-3β-methoxymethoxy-2-methylenebicyclo[3.1.0]hexane-1-methanol (21) which was prepared from the aldehyde(12) and the organostannane (16).