1032-16-2Relevant academic research and scientific papers
Mechanistic studies of deoxygenation of steroidal ring-D 16,17-ketols with trimethylsilyl iodide
Nagaoka, Masao,Nagasawa, Etsuko,Sato, Sadao,Numazawa, Mitsuteru
, p. 548 - 553 (2007/10/03)
Deoxygenation reaction of steroidal 16,17-ketols 1, 2 and 6 as well as their silyl ethers 3 and 7 and 16- and 17-iodoketone analogs 11, 12, and 14 with trimethylsilyl iodide (TMSI) or HI under various conditions was examined. The results indicate that the deoxygenation producing 16- and 17- ketones 9 and 8 proceeds through multiple reaction pathways; a direct iodination of a siloxy group of the ketol silyl ethers by iodide ion to give the iodoketones (path b), addition of TMSI to a carbonyl group of the ketol silyl ethers to yield diiodo derivatives 22 and 23 through iodo-bis-TMS compounds 20 and 21 (path a), and cleavage of ether bond of dimers 15-18 initially produced are, at least, involved. In these sequences, rearrangement of the 16-ketols 1 and 2 to the 17 β-ketol 6 also plays a significant role. The yields of the ketones 9 and 8 and their relative amounts would be dependent on the relative importance of each pathway in the reaction.
Deoxygenation of steroidal ring-D 16,17-ketols with trimethylsilyl iodide
Nagaoka, Masao,Nagasawa, Etsuko,Numazawa, Mitsuteru
, p. 1857 - 1861 (2007/10/03)
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.
