Sequential aza-Piancatelli rearrangement/Friedel–Crafts alkylation for the synthesis of pyrrolo[1,2-d]benzodiazepine derivatives

Abstract

2-Furylcarbinols undergo a smooth aza-Piancatelli rearrangement followed by Friedel–Crafts alkylation with a bifunctional substrate, (1H-pyrrol-1-yl)aniline, in the presence of 10 mol% In(OTf)₃ in acetonitrile at room temperature to afford the corresponding hexahydrobenzo[b]cyclopenta[f]pyrrolo[1,2-d][1,4]diazepin-11(4aH)-one scaffolds in good yields. This method offers significant advantages such as high conversions, mild reaction conditions, short reaction times, and high selectivity. The relative stereochemistry of the product was established by nOe studies.