Electrochemical reductive cascade cyclization of o -alkynylated derivatives for saturated amides/amines.

An unprecedented reductive hydroamidative/hydroquinazolinative cascade cyclization of o -alkynylated derivatives was achieved via proton-coupled electron transfer (PCET) under electrolysis. In a single step, the rapid assembly of isoindolinones and novel isoindole-fused quinazolinones were achieved through electrolysis by the hydroamidation of amidyl/quinazolinone aminyl radicals with C-C triple bond addition via 5- exo-dig cyclization followed by olefinic reduction without external reductants. Control and cyclic voltammetry experiments support a mechanistic explanation of the electrochemical cascade, and these experiments indicate that the electrolyte is the source of hydrogen for the olefin reduction.