Deoxygenation of steroidal ring-D 16,17-ketols with trimethylsilyl iodide

Article abstract of DOI:10.1248/cpb.46.1857

Reaction of various steroidal 16,17-ketols, 16α-hydroxy-17-ketones 1- 3, and 15, 16β-hydroxy-17-ketone 4, and 17β-hydroxy-16-ketones 5-7, and 17, along with methyl ethers of 16α- and 17β-ketols 1 and 5, with an excess of trimethylsilyl iodide (TMSI) or with HI in CHCl₃, produced the deoxygenated products, a mixture of the corresponding 17- and 16-ketones, in low to quantitative yields, in which the 17-ketone was the major product in each ease. When the 16β-deuterated 16α-ketol 3 and the 17α-deuterated 17β- ketol 7 were reacted with TMSI for a brief period (15 min), the deuterium content at C-16β and C-17α of the recovered steroids 3 and 7 was reduced by 17 and 35%, respectively. The present results indicate that the deoxygenation proceeds not only through a direct iodination pathway producing α-iodoketone but also through other reaction pathways.

Full text of DOI:10.1248/cpb.46.1857

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