Rh(III)-Catalyzed C–H Activation/Annulation of Benzohydroxamates and 2-Imidazolones: Access to Urea-Fused-Dihydroisoquinolone Scaffolds Reminiscent of Pyrrole Alkaloid Natural Products

Abstract

A Rh­(III)-catalyzed C–H activation/annulation with an imidazolone as alkene partner is reported to access dihydroisoquinolone-fused imidazolin-2-ones. These bicycles are reminiscent of scaffolds belonging to the pyrrole alkaloid family of natural products. This approach facilitates construction of a variety of urea-fused dihydroisoquinolone scaffolds including heterocyclic moieties.

The “cobra effect” in the imidazolinone series: how a donor can disable the nucleophilicity

“…12 In this context, imidazolin-2-ones are a special case of enamides possessing both "enamide" and "urea" motifs. Not only do they represent an interesting cross-conjugated system 13,14 but they are also valuable building blocks in alkaloid-like 15 and natural product [16][17][18][19][20] synthesis. They also serve as precursors for N-heterocyclic carbenes, [21][22][23] components of unnatural RNA base pairs 24 and FLP-type catalysts.…”