Synthesis of 24(28)-Methylene-1α-Hydroxyvitamin D<sub>3</sub>, a Novel Vitamin D<sub>3</sub> Analogue
作者:Wei Guo、Zhijie Fang、Hongliang Li、Yanan Liu
DOI:10.3184/174751914x13941144023496
日期:2014.4
24(28)-Methylene-1α-hydroxyvitamin D3 was synthesised in 13 steps from vitamin D2. The key step of the synthesis involved the Wittig–Horner olefination of a nor-vitamin D2 aldehyde with diethylphosphono-3-methyl-2-butanone. The resulting enone was followed by reduced methylenation, photoisomerisation and deprotection then gave the target compound.
Stereoselective synthesis of tacalcitol via ( R )-MeCBS catalyzed borane reduction
作者:Hengrui Zhang、Wei Guo、Zhijie Fang
DOI:10.1016/j.tetasy.2017.02.007
日期:2017.3
A novel and efficient approach for the synthesis of lot, 24(R)-dihydroxyvitamin D3 (tacalcitol) starting from readily available enone 1 has been achieved with high stereoselectivity. The key step involved in the synthesis of tacalcitol was the stereoselective reduction of enone 1 using borane as the reducing agent, and the effects of the critical reaction parameters such as temperature, various borane complexes have been examined. Finally, tacalcitol was obtained in five steps from enone 1 with an overall yield of 32% and a ratio of 24-R/S = 95/5. (C) 2017 Published by Elsevier Ltd.