Asymmetric total synthesis of an a-ring precursor to hormonally active 1α,25-dihydroxyvitamin D3

Article abstract of DOI:10.1021/jo00300a001

A new sulfinyl orthoester has been designed and used effectively in one-flask syntheses of dienoate esters from allylic alcohols; this new method as well as a highly stereocontrolled [2 + 4]-cycloaddition are applied to synthesis of 1α,25-dihydroxyvitamin D₃.