New approaches toward the synthesis of (D-homo) steroid skeletons using Mukaiyama reactions
作者:Florence C.E. Sarabèr、Alexander Baranovsky、Ben J.M. Jansen、Maarten A. Posthumus、Aede de Groot
DOI:10.1016/j.tet.2005.11.056
日期:2006.2
Mukaiyama reaction between the silylenolether of 6-methoxytetralone and 2-methyl-2-cyclopentenone or carvone, with transfer of the silylgroup to the receiving enone, gave a second silylenolether. Addition of a carbocation, generated under Lewis acid conditions from 3-methoxy-2-butenol, 3-ethoxy-3-phenyl-2-propenol or 3-methoxy-2-propenol to this second silylenolether gave adducts, which could not
A short, flexible and efficient procedure has been developed for the synthesis of C17 substituted steroid skeletons and D-homo steroid skeletons using a ZnBr2 catalysed coupling of a silyl enol ether containing ring D precursor with a Torgov type reagent, followed by acid catalysed cyclisation of the adducts to (D-homo) steroid skeletons.