Phenolic Oxidations of Totarol

Abstract

Methods for the direct oxidation of the C12 position of totarol (1) or its methyl ether (4) have been examined. Treatment of (1) with benzeneseleninic anhydride gave the 9-hydroxy dienone (16) which on ozonolysis afforded the spiro butenolide (21), formed via the ozonide (22). The rearranged ether (18) was obtained from one oxidation with benzeneseleninic anhydride. Mercuriation of totarol and totaryl methyl ether gave the mercuriochlorides (5) and (7) but attempts to form the methoxy acetate (6) from (7) by boronation /oxidation and acetylation were unsuccessful. Treatment of totaryl methyl ether (4) with thallium(III) trifluoroacetate gave dienone 14- and 9-trifluoroacetates (25) and (17). Reaction of the (η⁶-arene) tricarbonylchromium(0) complexes (28) and (29) of (4) with lithioacetonitrile gave the 7α-alcohol (30) but reaction with t- butyllithium and then with copper(I) bromide/ dimethyl sulfide and MoOPH gave the methoxyphenol (12) in 66% yield.