Cyanosilylation at pregnane side-chains. Selective synthesis and crystal structure of 20(R)-silylated cyanohydrins.
Trimethylsilylcyanide addition to different carbonyl moieties, i.e. saturated ketones, an enone and an aldehyde, at the steroid side-chain, was studied in the presence of a convenient catalyst. Depending on the nature of the carbonyl group, different outcomes were noticed. Saturated 20-keto pregnanes yielded epimerically pure silylated cyanohydrins, being the absolute configuration unambiguously established by X-ray crystallographic analysis.
Cruz Silva
M Manuel
MM
Centro de Estudos Farmacêuticos, Lab. Química Farmacêutica, Faculdade de Farmácia, Universidade de Coimbra, Coimbra 3000, Portugal.
Andrade
Lourdes C R
LC
Paixão
José A
JA
de Almeida
M José
MJ
e Melo
M Luisa Sá
ML
D002384:Catalysis; D018360:Crystallography, X-Ray / Q000379:methods; D003486:Cyanides / Q000737:chemistry*; D006868:Hydrolysis; D007659:Ketones; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D009570:Nitriles / Q000737:chemistry*; D011278:Pregnanes / Q000737:chemistry; D011487:Protein Conformation; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry; D014965:X-Rays
D003486:Cyanides; D007659:Ketones; D009570:Nitriles; D011278:Pregnanes; D013256:Steroids; C430593:cyanohydrin