The reaction of saccharin derivatives with N,N-didethylprop-1-ynamine; formation of cyclobutenyl saccharinates and of a spiro-oxete

Abstract

Saccharin and two equivalents of N,N-diethylprop-1-ynamine give a cyclobutenyl saccharinate (4), which, on bromination, gives the N-(cyclopbutenyl cation)saccharin derivative (8), whose structure was established by X-ray crystallography[only preliminary X-ray data available for (4)]; N-methylsaccharin reacts with one equivalent of ynamine to yield the spio-oxete (9); this represents the second isolation of such a stable oxete from reaction of an ynamine with a carbonyl group.