Pure Appl. Chem., 2008, Vol. 80, No. 5, pp. 1141-1148
http://dx.doi.org/10.1351/pac200880051141
Toward the total synthesis of ritterazine N
Abstract:
Zr-mediated equilibrating cyclocarbonylation of a designed triene led with high diastereocontrol to the ABC 6-6-5 tricyclic core of ritterazine N. The 5-5 EF spiroketal side chain of ritterazine N was prepared by equilibrating cyclization of an acyclic keto diol. The two components were coupled, and the D ring was assembled by intramolecular aldol condensation.