Efficient and versatile synthesis of A-ring precursors of 1α,25-dihydroxyvitamin D3 and analogues. Application to the synthesis of Lythgoe-Roche phosphine oxide

Article abstract of DOI:10.1016/S0040-4039(97)01005-8

An efficient, versatile synthesis of Lythgoe-Phosphine Oxide has been developed starting from l-carvene. The key steps are rupture of protected epoxide 7 to give dicarbonyl compound 8, preparation of vinylic triflate 2, and palladium-catalysed cyclization-carbonylation of vinylic triflate 2.