Synthesis of A‐Ring Precursors of 1α,25‐Dihydroxyvitamin D₃ Analogues Functionalized at C‐2

Abstract

A flexible approach to an A‐ring building block for new 1α,25‐dihydroxyvitamin D analogues functionalized at C‐2 as potential clinical candidates is described. The synthesis of alcohol 5 starts from (R)‐carvone, and uses a Criegee rearrangement to selectively degrade the isopropenyl side‐chain as one of the key steps.