An efficient procedure for the synthesis of spiro [furan-3, 3′-indolin]-2-ones and dispiro [cycloalkane-1, 2′-furan-3′, 3 ″-indolin]-2 ″-ones has been achieved in high yields and stereoselectivity by photoinduced electron transfer-catalyzed [3+ 2] reactions of substituted spiro [indoline-3, 2′-oxiran]-2-ones with olefins. The reactions proceed by ring opening of spiro [indoline-3, 2′-oxiran]-2-ones via Cβ–O bond cleavage and subsequent ...
