Photomediated Spirocyclization of N‑Benzyl Propiolamide with N‑Iodosuccinimide for Access to Azaspiro[4.5]deca-6,9-diene-3,8-dione

A metal- and oxidant-free route for affording azaspiro[4.5]­deca-6,9-diene-3,8-dione via photomediated iodinated spirocyclization of N-(4-methoxybenzyl) propiolamide has been developed. The reaction underwent a radical addition/ipso-cyclization/dearomatization process at room temperature and successfully constructed C–C and C–I bonds. This green and convenient approach could be generally expanded to produce a range of iodinated spirocyclization products in moderate to good yields.