ACTIVATION OF THE KETONE OF 5-CYCLODECENONES TOWARDS THERMAL TRANSANNULAR CYCLIZATION TO GIVE TRANS-HYDROAZULENOLS

The cyclization of 5-cyclodecenones substituted at C2 with an alkoxy g roup was examined. The alkoxy group sufficiently activates the ketone to allow for transannular cyclization upon heating, leading to trans f used hydroazulenols. In the cyclization of the 6-(trimethysilyl)methyl substituted 5-cyclodecenone, the TMS of the allylsilane is retained i n the product, leading to a vinylsilane product. Both the thermal and acid-induced cyclizations lead to products with a trans relationship b etween the oxygen substituents. (C) 1997 Elsevier Science Ltd.