The applicability of sulfoxide Michael acceptor--2-sulfinyl]-2-cyclopenten-1-one in constructing the carbon skeleton of 9,11-secosterols

A possibility of use of the Michael addition reaction of the A,B-ring fragment enolate to sulfoxide 2-(S)-[(4-methyl-phenyl)sulfmyl]-2-cyclopenten-1-one for constructing the main skeleton of 9,11-secosterols was studied. The reaction was conducted with the racemic or the enantiomerically enriched sulfoxide as the acceptor, affording a mixture of five or three main diastereomers, respectively. It was shown that the diastereoselectivity of that addition reaction is relatively low and does not afford a competitive new route for the total synthesis of secosterols. Keywords: Michael addition, sulfoxides, 9,11-secosterols.