Electrochemical Synthesis of gem-Difluoro- and γ-Fluoro-Allyl Boronates and Silanes

The electrochemical synthesis of fluorinated allyl silanes and boronates was disclosed. The addition of electrogenerated boryl or silyl radicals onto many alpha-trifluoromethyl or alpha-difluoromethylstyrenes in an undivided cell allowed the formation of a large panel of synthetically useful gem-difluoro and gamma-fluoroallyl boronates and silanes (64 examples, from 31 % to 95 % yield). In addition, a scale up of the reactions under continuous flow was showcased using an electrochemical reactor with promising volumetric productivity (688 g.L-1.h(-1) and 496 g.L-1.h(-1)). Moreover, the synthetic utility of these building blocks was highlighted through versatile transformations. Finally, plausible reaction mechanisms were suggested to explain the formation of the products.

Automated summary

The electrochemical synthesis of fluorinated allyl silanes and boronates was disclosed in this study. By adding electrogenerated boryl or silyl radicals onto various alpha-trifluoromethyl or alpha-difluoromethylstyrenes, a wide range of gem-difluoro and gamma-fluoroallyl boronates and silanes were successfully synthesized. The reactions were also scaled up under continuous flow conditions, demonstrating promising volumetric productivity. The synthetic utility of these building blocks was further highlighted through versatile transformations, and plausible reaction mechanisms were proposed to explain the formation of the products.