MgI 2 -Mediated Solvent-Controlled Divergent Ring-Opening Cyclization/Addition of Spirocyclopropyl Indanediones

-mediated formal (3 + 2) cycloaddition (ring-opening cyclization) and ring-opening iodination-Michael addition of spirocyclopropyl indanediones and nitroalkenes have been developed respectively in tetrahydrofuran and toluene, which constitutes an efficient protocol for the solvent-controlled divergent synthesis of spirocyclopentyl indandiones (up to 95% yield, >20:1 dr) and 2,2-disubstituted indanediones (up to 68% yield). Based on control experiments and a high-resolution mass spectrometry experiment, a plausible reaction mechanism has been proposed.