The dipolar route to naphtho[2,1‐<i>c</i>]isoxazoles from the baylis‐hillman adducts of 2‐alkynylbenzaldehydes

Abstract

Abstract magnified image A new synthesis of 4‐carbomethoxynaphtho[2,1‐ c ]isoxazoles 4a‐d from methyl 3‐(alkynylphenyl)‐2‐nitromethyl‐2‐propenoates 2a‐d by the intramolecular nitrile oxide cycloaddition is described. The latter are readily obtained from 2‐alkynylbenzaldehydes through the Baylis‐Hillman adduct acetates 1a‐d followed by nucleophilic substitution of nitrite anion.