Radical‐Dearomative Generation of Cyclohexadienyl Pd(II) toward the 3D Transformation of Nonactivated Phenyl Rings

Abstract

Traditional palladium‐catalyzed dearomatization of (hetero)arenes takes place via an ionic pathway and usually requires elevated temperatures to overcome the energy barrier of the dearomative insertion step. Herein, a combination of the radical and two‐electron pathways is disclosed, which enables room temperature dearomative 3D transformations of nonactivated phenyl rings with Pd(0) as the catalyst. Experimental results together with density functional theory (DFT) calculations indicate a versatile π‐allyl Pd(II) species, cyclohexadienyl Pd(II), possibly is involved in the dearomatization. This species is generated by combining the cyclohexadienyl radical and Pd(I). The cyclohexadienyl Pd(II) provides chemoselective (carboamination and trieneylation), regioselective (1,2‐carboamination), and diastereoselective (carbonyl‐group directed face selectivity) conversions.

Photoinduced Pd-Catalyzed Dearomative 2,5-Difunctionalizition of Furans via Cascade C–C/C–O Bond Formation

“…In recent years, photoinduced palladium catalysis has achieved a large number of organic conversions . It has been established by chemists represented by Gevorgyan, Fu, and Yu that hybrid alkyl palladium radical species can be generated via reductive cleavage of alkyl halides in the presence of photoexcited Pd(0) complexes . As part of our continuing interest in the conversion of furans, we believe that this strategy of photoinduced palladium catalysis can be applied to the dearomative 2,5-difunctionalization of furans as a complement.…”