title: C-H Functionalization via Remote Hydride Elimination: Palladium Catalyzed Dehydrogenation of ortho-Acyl Phenols to Flavonoids.
abstract: Although deprotonation of electron-poor C-H bonds to carbon anions with bases has long been known and widely used in organic synthesis, the hydride elimination from electron-rich C-H bonds to carbon cations or partial carbocations for the introduction of nucleophiles is a comparatively less explored area. Here we report that the carbonyl β-C(sp3)-H bond hydrogens of ortho-acyl phenols could be substituted by intramolecular phenolic hydroxyls to form O-heterocycles, followed by dehydrogenation of the O-heterocycle into flavonoids. The cascade reaction is catalyzed by Pd/C without added oxidants and sacrificing hydrogen acceptors.
authors.affiliation: School of Pharmacy, East China University of Science and Technology , Meilong Road 130, Shanghai 200237, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Pharmacy, East China University of Science and Technology , Meilong Road 130, Shanghai 200237, China.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Zhou
authors.affiliation: School of Pharmacy, East China University of Science and Technology , Meilong Road 130, Shanghai 200237, China.
authors.forename: Shuying
authors.initials: S
authors.lastname: Lin
authors.affiliation: School of Pharmacy, East China University of Science and Technology , Meilong Road 130, Shanghai 200237, China.
authors.forename: Xukang
authors.initials: X
authors.lastname: Jin
authors.affiliation: School of Pharmacy, East China University of Science and Technology , Meilong Road 130, Shanghai 200237, China.
authors.forename: Renhua
authors.identifier: 0000-0001-8253-6148
authors.initials: R
authors.lastname: Liu