Enamine chemistry. Part V. Reaction of αβ-unsaturated acid chlorides with enamines of medium and large ring ketones

Abstract

The reaction of αβ-unsaturated acid chlorides with enamines of medium and large ring ketones gives bicyclic (n, 3, 1) products, the nature of which is governed by the ability of the bridge-head position to accommodate a double bond in the 1-carbon bridge. When this is not possible the product is the iminium salt which is readily hydrolysed to the bicylic dione. With larger rings proton-loss from the iminium salt becomes increasingly more favourable to give bicyclic enamino-ketones, the lowest member of this series which has been isolated being 11-morpholinobicyclo[5,3,1]undec-7(11)-en-8-one.