Abstract
Lewis acid mediated Diels–Alder reactions of 2H-thiopyrans with acrylate, crotonate, and methacrylate dienophiles have been investigated. Modest to good yields of predominantly exo adducts are obtained with 4-substituted 2H-thiopyrans. With 5-substituted 2H-thiopyrans, high endo selectivity is observed. No adducts were produced with methacrylate dienophiles. Relative to the thermal reactions, the exo selectivity is enhanced in the presence of Lewis acids. Unusually high exo selectivity is observed using "wet" Et2AlCl as the promoter.
Publisher
Canadian Science Publishing
Subject
Organic Chemistry,General Chemistry,Catalysis
Cited by
16 articles.
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