Nucleophile singulett-carbene in der inversen [4+]-cycloaddition: Eine neue isopyrazol-synthese

Article abstract of DOI:10.1016/0040-4039(91)85074-F

Dimethoxycarbene, generated from the norbornadienone ketal 6 or from triethyl orthoformate 12a can be trapped by various 1,2,4,5-tetrazines 1 to yield the corresponding isopyrazoles 10 in high yields via [4+1]-cycloaddition followed by [4+2]-cycloreversio