TANDEM ANIONIC [3,3] SIGMATROPY AND SN' DISPLACEMENT - NEW SYNTHETIC TECHNOLOGY FOR THE CONSTRUCTION OF HYDROAZULENONE AND RELATED FRAMEWORKS

Transmetalation of the 3-(trimethylstannyl)-2-norcarenes 9 and 28b provides for the acquisition of optically pure bicyclic vinyllithium derivatives. These have been added to (±)-2-chlorocyclohexanone and the resultant ciS-chlorohydrins have been exposed to excess vinylmagnesium bromide under conditions which promote pinacol rearrangement and allow for subsequent 1,2-addition to the newly liberated carbonyl group. Following analysis of the response of divinyl carbinols 12 and 13 to anionic oxy-Cope rearrangement, the title process has been examined for 31-34. The precise conformational demands have been analyzed for each example. To some extent these are a function of the usual energetic advantages that accrue to chairlike conformations. However, other factors clearly contravene. These capabilities allow in turn for both syn and anti SN' displacement of methoxide ion. The sequential operation of a [3,3] sigmatropic step and SN' displacement is shown to be a powerful tool for rapid hydroazulenone construction. © 1990, American Chemical Society. All rights reserved.