Cationic cyclization of deuterated manool

Abstract

A test of the mechanism of acid-catalyzed cyclization of manool to 14α-hydroxyhibane was achieved by synthesis and cyclization of 7,7,9,17,17-pentadeuteriomanool. The reaction involves initial formation of a cyclooctenyl cation, an unusual in vitro step. The mass spectrum of the deuterated manool in relation to that of manool was used to analyze its fragmentation.