Catalytic Amide–Base System of TMAF and N(TMS)3 for Deprotonative Coupling of Benzylic C(sp3)–H Bonds with Carbonyls

This paper describes that an amide-base generated in situ from tetramethylammonium fluoride (TMAF) and N(TMS)3 catalyzes the deprotonative coupling of benzylic C(sp3)-H bonds with carbonyls to form stilbenes. A variety of methylheteroarenes (2-methylbenzothiophene, 2-methylbenzofuran, and 2-, 3-, or 4-methylpyridines) are used as nucleophiles. Application to enamine synthesis using DMF as an electrophile is also shown. The present system is effective for toluenes (4-phenyl-, 4-bromo-, 2-bromo-, and 4-chlorotoluenes) having low reactivity.