A new preparation of 1,3,3-trimethylbicyclo[2.2.2]octan-2,6-dione, a never isolated intermediate in a total synthesis of (+)-norpatchoulenol. Formal total synthesis of (+/-)-iso-norpatchoulenol

摘要

A new preparation and the isolation and spectroscopic characterization of 1,3,3-trimethylbicyclo[2.2.2]octan-2,6-dione (3), a so far elusive key intermediate in the Liu-Ralitsch total synthesis of (+)-norpatchoulenol ((+)-1a), is described. The preparation of 3 constitutes also a formal total synthesis of (+/-)-iso-norpatchoulenol ((+/-)-1b), since 3 is correlated to an intermediate in the Monti and co-workers synthesis of (+/-)-1b.