Metal Free Dötz-Type Aminobenzannulation Reaction via 1,1-Dipoles Cross-Coupling

Angew Chem Int Ed Engl. 2023 Oct 9;62(41):e202310133. doi: 10.1002/anie.202310133. Epub 2023 Sep 1.

Abstract

Aryl amines are of constant interest in organic synthesis owing to their ubiquity in natural products, pharmaceuticals, and organic materials. However, C-H amination or pre-functionalization frequently results in uncontrollable site selectivity, over activation and the generation of inseparable mixtures of regio-isomers. Here we present a novel metal free Dötz-type aminobenzannulation reaction that circumvents the selectivity issues inherent in aromatic chemistry, as well as the use of stoichiometric unstable organolithium reagents and toxic chromium complexes. The concept of utilizing readily available isocyanides and Morita-Baylis-Hillman (MBH) carbonates to achieve 1,1-dipoles cross-coupling to construct ketenimine is the key to success, which has been experimentally and computationally verified. The tandem 6π-electrocyclization/aromatization process offers a versatile method for synthesizing functionalized anilines, fused aryl amines and fused heteroaryl amines.

Keywords: 1,1-Dipole; Amines; Cross-Coupling; Dötz Reaction; Ketenimine.