Ionic hydrogenation of C-20, 22-ketene dithioacetal: stereoselective synthesis of steroidal C (20R) aldehydes.
نویسندگان
چکیده
Homologation of 16-dehydropregnenolone acetate leads to excellent stereocontrolled synthesis of unnatural C (20R) aldehydes and through compound .
منابع مشابه
Studies on Wittig rearrangement of furfuryl ethers in steroidal side chain synthesis
Wittig rearrangement of 17(20)-ethylidene-16-furfuryloxy steroids 5–8 was examined. Reaction of 17E(20)-ethylidene-16afurfuryloxy steroid 5 with t-BuLi in THF afforded (20S,22S)and (20S,22R)-22-hydroxy steroids 9, 10 and 17Z(20)-ethylidene-16a-(2furyl)hydroxymethyl steroid 11 in 61, 28, and 9% yields, respectively. Base treatment of 17E(20)-ethylidene-16b-furfuryloxy steroid 7 gave (20R,22R)-22...
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Some ZO-P-tolyl analogs of ZOa-hydroxycholesterol and cholesterol have been synthesized and tested as precursors of pregnenolone. As in the previously synthesized t-butyl analog, (20R)-20-f-butyl-5-pregnene-3~,20-diol. C-22 in these synthetic compounds is completely substituted and therefore unavailable for biological hydroxylation (1). (20R)-20-(&Tolyl)-5-pregnene-3P,20-diol, I, when incubated...
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ورودعنوان ژورنال:
- Chemical communications
دوره 19 شماره
صفحات -
تاریخ انتشار 2004