Selective acceleration of disfavored enolate addition reactions by anion-? interactions.

ABSTRACT: In chemistry and biology, cation-? interactions contribute significantly to many important transformations. In sharp contrast, reactions accomplished with support from the complementary anion-? interactions are essentially unknown. In this report, we show that anion-? interactions can determine the selectivity of the enolate chemistry of malonate half thioesters. Their addition to enolate acceptors is central in natural product biosynthesis but fails without enzymes because non-productive decarboxylation dominates. The newly designed and synthesized anion-? tweezers invert this selectivity by accelerating the disfavored and decelerating the favored process. The discrimination of anionic tautomers of different planarization and charge delocalization on ?-acidic surfaces is expected to account for this intriguing "tortoise-and-hare catalysis." Almost exponentially increasing selectivity with increasing ? acidity of the catalyst supports that contributions from anion-? interactions are decisive.

SUBMITTER: Zhao Y 

PROVIDER: S-EPMC6054047 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature