Studies of vitamin D (calciferol) and its analogs. 42. 3-Deoxy-3-thia-1. alpha., 25-dihydroxyvitamin D3 and its 1. beta.-epimer: synthesis and biological evaluation
AS Lee, AW Norman, WH Okamura
文献索引：Lee, Adam S.; Norman, Anthony W.; Okamura, William H. Journal of Organic Chemistry, 1992 , vol. 57, # 14 p. 3846 - 3854
The syntheaea of 3-deoxy-3-thia-la, 25-dihydroxyvitamin D3 (Sa) and its@ epimer Sb have been achieved starting from CD-fragment 10 and the enantiomerically pure A-rings lla and llb prepared from thia 1, 3-diketone 13. For the preparation of lla and llb, the thia diketone 13 was converted in two steps to the trimethylsilyl enynone 18. In the most effective route, the latter was asymmetrically reduced using (R)-or (5')-oxazaborolidine 24 and 25 and ...
