Dual Chalcogen-Chalcogen Bonding Catalysis.

The noncovalent S···O bonding interaction is an evolutionary force that has been smartly exploited by nature to modulate the conformational preferences of proteins. The employment of this type of weak noncovalent force to drive chemical reactions is promising yet remains largely elusive. Herein, we describe a dual chalcogen-chalcogen bonding catalysis strategy that the distinct chalcogen atoms simultaneously interact with two chalcogen-based electron donors to give rise to the catalytic activity, thus facilitating chemical reactions. Conventional approaches to the Rauhut-Currier-type reactions require the use of strongly nucleophilic Lewis bases as essential promoters. The implementation of this dual chalcogen-chalcogen bonding catalysis strategy allows the simultaneous Se···O bonding interaction between chalcogen-bonding donors and an enone and an alcohol, enabling the realization of the Rauhut-Currier-type reactions in a distinct way. The further implementation of a consecutive dual Se···O bonding catalysis approach enables the achievement of an initial Rauhut-Currier-type reaction to give an enone product which further undergoes an alcohol-addition induced cyclization reaction. This work demonstrates that the nearly linear chalcogen-bonding interaction can differentiate similar alkyl groups to give rise to regioselectivity. Moreover, the new strategy shows its advantage as it not only enables less reactive substrates working efficiently but tolerates inaccessible substrates using conventional methods.