Conjugate Additions to Alkylidene Bis(Sulfoxides)

A general study on the conjugate addition of anionic nucleophiles to alkylidene bis(sulfoxides) is presented. Alkoxides gave high yielding and diastereoselective addition reactions, which could be influenced by solvents and the counteranion. Azides provided an interesting entry into sulfinyl‐substituted triazoles. Organometallics, mainly copper reagents, proved also to be valuable nucleophiles, and complete inversion of the stereoselectivity was achieved in the addition reaction with the latter. Modelizations provide a rationale for the observed diastereoselectivity. Taking the Michael: Alkylidene bis(sulfoxides) are exquisite Michael acceptors toward a broad series of nucleophiles, and in most cases the reaction affords the adducts in high yields with complete diastereoselectivity. Copper reagents are also good nucleophiles in this reaction, but proceed with an inversion in stereoselectivity. Rationalization was provided by DFT calculations.