Green synthesis of α-deuterated boronates using DMTT reagent

An efficient method for the synthesis of deuterated homologation of boronate esters was developed. This discovery uses robust deuterated agent 5-(methyl-d3)-5H-dibenzo[b,d]thiophen-5-ium trifluoromethane sulfonate (DMTT) as d2-methylene source. Mechanistically, base promoted deprotonation of DMTT to generate d2-sulfur-methylene ylide intermediate, which attack the boron atom of boronic ester and followed by 1,2-migration to afford the deuterated boronic homologues. The developed protocol provides a unique approach to achieve one-carbon growth under the practical mild conditions.