A thermally-induced, tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition approach to carbocyclic spirooxindoles

• Kay M. Brummond and
• Joshua M. Osbourn

Beilstein J. Org. Chem. 2010, 6, No. 33, doi:10.3762/bjoc.6.33

• observed, but are likely intermediates of an infrequently encountered thermal [3,3]-sigmatropic rearrangement of a propargylic acetate. Keywords: allene; propargylic acetate; spirooxindole; thermal [2 + 2] cycloaddition; thermal [3,3]-sigmatropic rearrangement; vinylidene indolin-2-one; Introduction

• , the feasibility of this method for the preparation of spirooxindole alkaloids was investigated. The preliminary results of this study are reported herein. Results and Discussion To begin the investigation, the first challenge was the preparation of a functionalized vinylidene indolin-2-one 5 (Figure 2

• Kay M. Brummond Joshua M. Osbourn Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A 10.3762/bjoc.6.33 Abstract The synthesis of C3-carbocyclic spirooxindoles was realized by way of an intramolecular [2 + 2] cycloaddition reaction between a vinylidene indolin