Résumé
New developments in the reduction of b,d-diketo-sulfoxides, a reaction that affords important key intermediates for total synthesis, are described. We showed without ambiguity using NMR experiments, that the b-carbonyl group is totally enolised. This result is inconsistent with the previous hypothesis, which supposed the other tautomer (enolisation at the d-position) as the major one. We propose a rationale to explain the side reactions occurring during the reduction of unprotected b,d-diketo-sulfoxides and showed that judicious protection of the d-carbonyl group gave all diastereoisomers of b-hydroxy-d-ketosulfoxides.