Studies of vitamin D (calciferol) and its analogs. 35. Synthesis and biological activity of 9,11-dehydrovitamin D3 analogs: stereoselective preparation of 6.beta.-vitamin D vinylallenes and a concise enynol synthesis for preparing the A-ring
Studies of vitamin D (calciferol) and its analogs. 35. Synthesis and biological activity of 9,11-dehydrovitamin D3 analogs: stereoselective preparation of 6.beta.-vitamin D vinylallenes and a concise enynol synthesis for preparing the A-ring