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J. Org. Chem. 1997, 62, 8980-8986
Articles Oligomerization of the Thiophene-Based p-Quinodimethanes 2,5-Dimethylene-2,5-dihydrothiophene and 2-Ethylidene-5-methylene-2,5-dihydrothiophene Walter S. Trahanovsky,* Deborah Louise Miller, and Yili Wang Department of Chemistry, Iowa State University, and Ames Laboratory, Ames, Iowa 50011-3111 Received August 6, 1996X
Flash vacuum pyrolysis (FVP) of (5-methyl-2-thiophene-yl)methyl benzoate (8) produces in ca. 75% yield 2,5-dimethylene-2,3-dihydrothiophene, S-monomer (3). S-Monomer 3 is relatively stable dissolved in carbon disulfide-chloroform at -78 °C. The structure of 3 is confirmed by its spectral properties. When a 0.17 M solution of S-monomer 3 was allowed to warm to room temperature, SS-dimer 5 ([2,2](2,5)thiophenophane, 14.7%), SSS-trimer 7 ([2,2,2](2,5)thiophenophane, 44.3%), and polymer were produced. A small amount (
