The vinylsulfonamides 3 of the furan-containing N-benzylamines 2 cycli
ze at room temperature to give the delta-sultams 4 with high diastereo
selectivity. For the vinylsulfonamides 6 featuring a three atom tether
connecting the furan and the dienophile moieties, the equilibrium bet
ween 6 and the gamma-sultam 7 is largely shifted towards 7 for N-benzy
l substituted 6c in refluxing toluene.