19257-34-2Relevant articles and documents
Novel Insertion, Rearrangement and Addition Products from Dihalogenocarbene Reactions with 5(10)-Unsaturated Steroids
Templeton, John F.,Ling, Yangzhi,Lin, Weiyang,Pitura, Randy J.,Marat, Kirk,Bridson, John N.
, p. 1149 - 1158 (2007/10/02)
Novel insertion, rearrangement and addition products from dibromocarbene and dichlorocarbene reactions with 5(10)-unsaturated steroids have been identified.The dihalogenocarbenes were prepared under phase-transfer conditions (CHBr3- or CHCl3-NaOH), and from CHBr3-KOBut-Et2O, phenyl(trichloromethyl)mercury and sodium trichloroacetate.Evidence that the major products arise from an initial dihalogenocarbene reaction on the α face of the molecule is reported.The major products obtained from addition of CBr2 to 3,17-disubstituted estr-5(10)-enes, after ketal hydrolysis, were 19(S)-bromo-9α,19-cyclo-10α-androst-4-en-3-one and 3',3',19(S)-tribromo-3'H-9α,19-cyclopropa-5β,10α-androstan-3-one derivatives together with the 19,19-dibromo-5α,19-cyclo-10α-steroid adduct.No products from addition of CBr2 to the β-face of the double bond, as previously reported, were identified.Reactions of CCl2 gave, besides rearrangement products analogous to those obtained from CBr2, a 5α-hydroxy-9α,19α-cycloandrostane derivative, the 9α-CHCl2 insertion derivative and both α- and β-face addition products to the double bond.Structures were established by homonuclear and heteronuclear correlation and nuclear Overhauser effect NMR measurements and X-ray crystallography.
