Platinum-Catalyzed Intramolecular Hydroarylation of Allenyl Arenes: Efficient Synthesis of 1,4-Dihydronaphthalenes

An efficient synthetic method of 1,4-dihydronaphthalenes having various alkyl groups on the 4-position and/or ethoxycarbonyl group on the 2-position through selective intramolecular Pt-catalyzed 6-endo cyclohydroarylation of ethyl 2-benzy1-2,3-alkadienoates was developed. The present method could be further extended to two-fold Pt-catalyzed 6-endo and 7-endo cyclizations.