Selective ortho C-H Cyanoalkylation of (Diacetoxyiodo)arenes through [3,3]-Sigmatropic Rearrangement

Abstract

We herein report a robust catalyst-free cross-coupling between ArI(OAc)₂ and α-stannyl nitriles, aided by TMSOTf. The transformation introduces a cyanoalkyl group to the ortho position of ArI(OAc)₂ and simultaneously reduces the aryl iodine(III) to iodide, thus providing α-(2-iodoaryl) nitrile as the product. This transformation could be completed within 5 min at -78 °C and features superb functional-group tolerance and efficient scalability. DFT calculations indicate that the formation of a ketenimine(aryl)iodonium intermediate and subsequent [3,3]-sigmatropic rearrangement are involved as key steps.

Keywords: cyanoalkylation; electrophilic activation; hypervalent iodine; organotin reagents; sigmatropic rearrangement.