A cyclopropanol derivative as an intermediate for the preparation of A-homopimarane

Abstract

The hydroxycyclopropane (4) and the cyclobutanone (3) derivatives of isopimara-7,15-diene were prepared by the reduction of 3-oxo-19-tosyloxy isopimara-7,15-diene (2) with zinc and sodium iodide in hexamethylphosphoric triamide. On exposure to air compound (4) was oxidized to give the peroxide (6), in equilibrium with the corresponding hydroperoxide (7). The sequence (2)→(4)→(6) represents a new route to A-homopimaranes.