Visible light-mediated metal-free double bond deuteration of substituted phenylalkenes

Various bromophenylalkenes were reductively photodebrominated by using 1,3-dimethyl-2-phenyl-1H-benzo-[d]imidazoline (DMBI) and 9,10-dicyanoanthracene. With deuterated DMBI analogs (the most effective was DMBI-d(11)), satisfactory to excellent isotopic yields were obtained. DMBI-d(11) could also be regenerated from the reaction mixtures with a recovery rate of up to 50%. The combination of the photodebromination reaction with conventional methods for bromoalkene synthesis enables sequential monodeuteration of a double bond without the necessity of a metal catalyst.

Automated summary

In this study, various bromophenylalkenes were reductively photodebrominated using DMBI and 9,10-dicyanoanthracene, with satisfactory to excellent isotopic yields achieved with deuterated DMBI analogs. DMBI-d(11) was the most effective analog, and it could also be regenerated from the reaction mixtures with a recovery rate of up to 50%. The combination of photodebromination reaction with conventional methods for bromoalkene synthesis allows for sequential monodeuteration of a double bond without the necessity of a metal catalyst.