Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester

Abstract

An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene) of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

Keywords

• dipolar cycloaddition
• heterocycle
• nitrile oxide
• hypervalent iodine oxidation
• pinacol boronic acid esters