Divergent Synthesis of Organofluorinated Molecules from Titanium Mediated Deoxygenation of Free Alcohols

Comprehensive SummaryAlcohols as among the most widely occurring organic compounds known, deoxygenative transformations of free alcohols as partners in radical addition reactions remain formidable challenges with great opportunities to achieve new and useful transformations. Herein, we report a protocol via C-O bond cleavage and C-C bond-forming reaction of trifluoromethyl alkenes with free alcohols assisted by titanium reagents via a deoxygenative radical strategy, enabling the divergent synthesis for functional-group-rich organofluorinated compounds in high efficiencies. In this transformation, tertiary alcohols by Ti-catalysis could be converted to trifluoromethyl alkanes without defluorination in acidic conditions, while benzyl alcohols are employed by Ti-mediated activation to supply the gem-difluoroalkenes with defluorination in the presence of a base. This protocol is applicable for a broad range of trifluoromethyl alkenes with good functional group tolerance and a variety of tertiary alcohols and benzyl alcohols (including primary, secondary, and tertiary alcohols), and is scalable to the gram level. Remarkably, the utility of this protocol is demonstrated by several derivatizations and late-stage functionalization of drug molecules. The successful applications in scale up reactions and late-stage functionalization of several drug molecules demonstrate its potential synthetic value in drug discovery settings.