The 1,3-dipolar cycloaddition of 3,4,5,6-tetrahydropyridine 1-oxide, 1, to 2(5H)-furanones 2, 3, and 4 is investigated. Crucial nmr data are indicated to determine the conformational equilibria and stereochemistry of the adducts. The major products arise from exo transition states. © 1992.
- 1,3-dipolar cycloaddition
- 3,4,5,6-tetrahydropyridine 1-oxide