Angewandte Chemie International Edition
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Back Cover: Scope and Mechanism of the (4+3) Cycloaddition Reaction of Furfuryl Cations (Angew. Chem. Int. Ed. 50/2011)
The method of choice for the preparation of six-membered rings is (4 + 2) cycloaddition. The isoelectronic (4 + 3) cycloaddition between a diene and an allyl cation gives seven-membered rings, but the synthesis of suitable cationic reaction partners is challenging. In their Communication on page 11990 ff., J. M. Winne et al. report a novel synthetic method that uses furfuryl alcohols as three-carbon dienophiles for the rapid assembly of cycloheptenes.