Enantioselective Synthesis of Inherently Chiral Tetraphenylene Analogues Enabled by NHC‐Catalyzed Benzoin Condensation

ABSTRACT Herein, we report an enantioselective N‐heterocyclic carbene (NHC)‐catalyzed intramolecular benzoin reaction of bisaldehydes featuring a 1,1′:2′,1′′‐terphenyl linkage to afford eight‐membered α‐hydroxy ketones in which six of the eight ring atoms are benzene carbons. The benzene‐rich framework is conformationally inflexible and thus inherently chiral, adopting a saddle‐shaped conformation. A variety of heteroaromatic‐ and naphthalene‐embedded tetraphenylene analogues were prepared enantioselectively by routine transformations of the α‐hydroxy ketone moiety. Density functional theory (DFT) calculations elucidate the reaction mechanism and provide insights into the origin of the stereoselectivity.