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Catalytic, formal homo-Nazarov-type cyclizations of alkylidene cyclopropane-1,1-ketoesters: access to functionalized arenes and heteroaromatics.

Research paper by Joel J Aponte-Guzmán, J Evans JE Taylor, Elayna E Tillman, Stefan S France

Indexed on: 09 Jul '14Published on: 09 Jul '14Published in: Organic Letters



Abstract

A catalytic, formal homo-Nazarov-type cyclization of alkylidene cyclopropanes (ACPs) to give functionalized arenes and heteroaromatics is reported. In the presence of a Lewis acid catalyst, the ACP 1,1-ketoesters undergo distal bond cleavage to afford an allyl cation intermediate. Adjacent π-attack on the allyl cation then provides a six-membered ring that undergoes rapid aromatization. In these cases, benzenoid products are formed in up to 98% yield. Strategic choice of the substitution about the ACP allows for the generation of other useful isomeric products in good yields.