Palladium-catalyzed [4 + 3]-annulations of oxotryptamines with allyl dicarbonates: an approach toward spiro[azepane-4,3′-oxindoles]

A palladium-catalyzed tandem allylic substitution of oxotryptamines with allyl dicarbonates has been developed, affording spiro[azepane-4,3′-oxindoles] in moderate to excellent yields (30%–96%) with up to >20 : 1 Z -stereoselectivity.