Spiro Oxadiazolines - Source of Cyclic Dioxa Carbenes

Abstract

<p> It is known that alkoxyoxadiazolines undergo thermal decomposition to form carbenes via an ylide intermediate. This project involved the preparation and subsequent thermolysis of spirooxadiazolines of type 4.</p> <p> Spiro oxadiazoline (4) was prepared by oxidation of (3) with lead tetraacetate in dichloromethane. The first order rate constant for the thermolysis of 4b in benzene at 111°C is determined. The primary thermolysis products were found to be acetone, nitrogen and the cyclic dioxacarbene (5). Formation of (5) was confirmed by various trapping experiments. (See Diagram in Thesis)</p>