Synthesis of Densely Substituted Spirocyclobutanes from Activated Alkenes and Sulfur Ylides
Maksim A Boichenko1, Timur P Tikhonov1, Vitaly V Shorokhov2
1Department of Chemistry, M. V. Lomonosov Moscow State University, Leninskie gory 1-3, Moscow 119991, Russia.
Abstract:
We report the direct synthesis of densely substituted spiroannulated cyclobutanes from indane-1,3-dione-based activated alkenes or their analogs and sulfur ylides under mild, Lewis acid-free conditions. The transformation proceeds through a Corey-Chaykovsky cyclopropanation that furnishes highly strained donor-acceptor spirocyclopropanes, followed by their (3 + 1)-annulation with stabilized sulfonium ylides that can be conducted in a telescoped or one-pot fashion. Preliminary mechanistic studies allowed a better understanding of the origin of both the observed high reactivity and diastereoselectivity.
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