An asymmetric synthesis of a 1α,25-dihydroxyvitamin D3 A-ring synthon

Article abstract of DOI:10.1016/0040-4039(92)88109-I

An efficient asymmetric synthesis of the A-ring of 1α,25-dihydroxyvitamin D₃ from α-bromoacrolein is described. The key steps of the synthesis are the Evans type syn-selective asymmetric aldol reaction of bromoacrolein with the boron enolate of