Diastereoselective [3+2] cycloadditions of a camphor-derived chiral N-acryloylhydrazide with nitrile oxides: the preparation of optically pure Δ2-isoxazolines
Reaction of a novel chiral N-acryloylhydrazide with various nitrile oxides proceeded smoothly to afford the cycloadduct with high diastereoselectivity (99:1). The auxiliary can be easily removed from the cycloadducts under mild conditions.
An efficient 1,3-dipolar cycloaddition between aromatic selenoaldehydes and nitrile oxides or nitrile imines: an easy access to selenium-containing five-membered heterocyclic ring system
1,3-Dipolar cycloaddition between aromatic selenoaldehydes, generated by thermal retro Diels–Alder reaction of anthracene cycloadducts, and nitrileoxides or nitrile imines proceeded efficiently to give the corresponding [3+2] cycloadducts as a single isomer in good yields, being 1,4,2-oxaselenazoles or 1,3,4-selenadiazoles, respectively.