The first synthesis and biological testing of the enantiomer of 1α,25-dihydroxyvitamin D3

The 1α,25-dihydroxyvitamin D3 enantiomer was synthesized and examined in biological tests. The ring A precursor was prepared from vitamin D2 employing the Mitsunobu reaction for inversion of the configuration at C-3 and SeO2 hydroxylation at C-1. The CD rings-side chain portion was synthesized from an optically active hexanoic acid derivative using diastereoselective tandem Mukaiyama–Michael addition and vinylsulfone reduction as the key steps. The ring A and CD rings building blocks were combined using the Julia alkenylation reaction. 1α,25-Dihydroxyvitamin D3 enantiomer shows no significant affinity to the vitamin D receptor.