Studies toward the enantioselective total synthesis of 3/spl alpha/-hydroxy-15-rippertene

The tetracyclic diterpene 3/spl alpha/-hydroxy-15-rippertene (1) was isolated from the defensive secretion of the higher termites Nasutitermes rippertii and Nasutitermes ephratae by Prestwich et al. Herein we report the synthesis of two advanced hydroazulene key intermediates for the enantioselective total synthesis of 1.