ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Δ16-20-Ketosteroids by C2-Elongation from Δ16-17-Substituted SteroidsReactions of corticoid precursor steroids with a Δ16-double bond and iodine, trimethylsilyl, tributylstannyl or trifluoromethanesulfonyloxy groups in 17-position were studied with the aim of introducing an acyl substituent in 17-position. Starting with the 17-trimethylsilyl compounds, using acyl chlorides and AlCl3 as a catalyst, a mixture of chlorinated compounds were obtained, among others. Better results gave palladium-catalyzed reactions, such as the cross-coupling of 17-tributylstannyl compounds with acyl chlorides or the substitution of the 17-iodides or the 17-triflates by vinyl ethers. In the reaction of the 17-iodides, different protecting groups are tolerated; thus this method is of general use. No Δ16-17-triflates were obtained by the reaction of androsta-4-ene-3, 17-dione or androsta-1,4-diene-3, 17-dione with trifluoromethanesulfonyl anhydride. This is a limitation of the triflate method, which in the other cases gives the best yields (〉80%).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19933350508
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