Cycloadditions of Nitrile Oxides to the Highly Reactive N-Acyl 2-Oxa-3-Azanorborn-5-enes Afford Versatile Cycloadducts and a Convenient Entry to Highly Functionalized Derivatives

N-Acyl-2-oxa-3-azanorborn-5-enes are highly reactive dipolarophiles in cycloadditions with nitrile oxides. The cycloadducts can be easily elaborated to various functionalized structures that are not directly accessible by 1,3-dipolar cycloadditions.