We report a highly enantioselective and efficient synthesis of C-3 substituted butenolides via a tandem C-H activation/Michael addition cascade, enabled by Rh/cinchonine dual catalysis. This strategy leverages the stability and accessibility of the achiral Cp*RhCl22 complex in combination with the chiral induction provided by the naturally occurring alkaloid cinchonine, eliminating the need for complex chiral ligands. Importantly, this dual catalytic system represents the first enantioselective protocol that exploits simple acrylic acids as coupling partners, thereby extending the reactivity paradigm beyond conventional benzoic acid derivatives and significantly broadening the substrate scope beyond aromatic counterparts. The reaction proceeds in a one-pot fashion under mild conditions, delivering a wide range of products with good to very good enantiomeric excess.
Dethe et al. (Fri,) studied this question.