Herein we report the 3,5-bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C-H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C-H insertion and Friedel-Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen-bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C-O bonds. Despite the highly Lewis-acidic nature of these catalysts that enables triflate abstraction from sp carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis-basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.
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| http://dx.doi.org/10.1021/acs.orglett.0c01745 | DOI Listing |
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