Octadienyl carbonates 5 provide cyclic 1,4-dienes 6 when treated with Rh1 complexes (1–10 mol-%) at 80°. Similar cyclization of cyclohexenyl acetate 8 affords cis- fused hexahydroindene 9. Analogous ring closures of nonadienyl carbonate 10 yield preferably the cis-divinypyrrolidine 11 with Rh1 catalysis but the trans-isomer 12 when catalyzed by Pd0. Azaoctadienyl carbonate 5a undergoes elimination with [RhH(PPh3)4] (5 mol-%, 80°) in MeCN giving acyclic triene 7.