MEDIUM-RING AND LARGE-RING HETEROCYCLIC-SYSTEMS BY INTRAMOLECULAR NITRILE IMINE CYCLOADDITIONS

A series of hydrazonyl chlorides bearing an alkenyl chain have been sy nthesised and treated with silver carbonate. The propensity of the so- formed nitrile imine intermediates to undergo intramolecular cycloaddi tion is markedly dependent on the length and the flexibility of the ch ain. The latter also affected the regio- and the stereo-chemistry of t he intramolecular process. In certain circumstances, tandem intermolec ular-intramolecular cycloadditions took place, to produce large-ring h eterophanes.