Triphenyltin hydride-promoted reaction of β-lactam-tethered bromodienes gave six-,
seven-, or eight-membered bicyclic ring structures through intramolecular free radical
cyclization. The cyclization precursors were synthesized by stereoselective tin-mediated
carbonyl bromoallylation of 4-oxoazetidine-2-carbaldehydes in an aqueous environment.
carbonyl additions - cyclizations - lactams - radical reactions - tin