A novel and practical route to the A-ring enyne synthon (2), which can be versatile for a variety of A-ring analogs of 1 alpha,25-dihydroxyvitamin D3 (1), was developed. This novel method led to an improved synthesis of the A-ring diastereomers of 1, the compounds 13-15, and synthesis of the new analogs, 2-methyl-1,25-dihydroxyvitamin D3 (4) with its all possible diastereomers. The biological evaluation of the 2-methyl analogs showed the alpha alpha beta-isomer to be more potent than 1.