Syntheses of (?)-Cryptocaryolone and (?)-Cryptocaryolone Diacetate via a Diastereoselective Oxy-Michael Addition and Oxocarbenium Allylation

摘要

The total syntheses of both (−)-cryptocaryolone and (−)-cryptocaryolone diacetate is presented herein. The usage of a diastereoselective oxy-Michael addition/benzylidene acetal formation coupled with a selective axial oxocarbenium allylation allowed for the preparation of the α-C-glycoside moiety present in the bicyclic bridged structure. In addition, the syn-1,3-diol of the linear portion was installed via a Wacker oxidation followed by a subsequent directed reduction of the appropriate homoallylic alcohol precursor.