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Communication | Special issue | Vol 76, No. 1, 2008, pp.227-235
Published online, 24th April, 2008
DOI: 10.3987/COM-08-S(N)55
Diene-Transmissive Hetero-Diels-Alder Cycloaddition Using Cross-Conjugated Dioxatrienes: A Novel Synthesis of Tetrahydropyran-Fused Aza- and Thia-heterocycles

Takao Saito,* Satoru Kobayashi, Takashi Otani, Hideoki Iwanami, and Takayuki Soda

*Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan

Abstract

The diene-transmissive hetero-Diels-Alder methodology using cross-conjugated dioxatrienes [2-(R-methylene)propanedials] has been developed. The initial cycloaddition with electron-rich dienophiles, followed by the reactions of the resulting 1-oxadiene moiety of the monoadducts with amines and Lawesson’s reagent generated 1-azadienes and 1-thiadienes. The second hetero-Diels-Alder reaction of these reactive heterodienes with dienophiles (tosyl isocyanate, diphenylketene, enones, and maleinimide) produced pyran-fused aza- and thiaheterocycles, providing a new synthetic method for these heterocycles.