Construction of boron-stereogenic BODIPYs through organo-catalyzed enantioselective formal C(sp²)-O/O-H metathesis.

Abstract

The development of organo-catalyzed C(sp²)-O functionalization has gained significant importance in modern synthetic chemistry. However, a practical and general strategy for constructing chiral molecules via this approach remains elusive. Here we report an organo-catalyzed enantioselective formal C(sp²)-O/O-H cross metathesis using alcohols as nucleophiles and boron dipyrromethene (BODIPY) dyes as a class of valuable substrates to validate this concept. A series of boron-stereogenic α,α-di-alkyloxyl/aryloxyl BODIPYs have been achieved in up to 97% yields with 99.8% ee. Notably, detailed mechanistic studies reveal the crucial roles of both nucleophile and leaving-group, suggesting that the reaction might proceed via a concerted nucleophilic aromatic substitution pathway. Computational studies further indicate potential interactions among the BODIPY substrate, nucleophile, and chiral catalyst through multiple hydrogen bonds, achieving excellent enantioselectivity via a proton-transfer process. Moreover, these chiral BODIPY derivatives exhibit promising photophysical properties, highlighting their potential as chiral fluorescent probes or optoelectronic materials.