Enantioselective Organocatalytic Intramolecular Diels−Alder Reactions. The Asymmetric Synthesis of Solanapyrone D
作者:Rebecca M. Wilson、Wendy S. Jen、David W. C. MacMillan
DOI:10.1021/ja054008q
日期:2005.8.24
The first direct enantioselective organocatalytic intramolecularDiels-Alderreaction has been accomplished. The use of iminium catalysis has provided a new catalytic strategy for the enantioselective [4 + 2] cycloisomerization of a wide variety of tethered diene-enal systems. The use of imidazolidinones 1 and 2 as the asymmetric catalysts has been found to mediate the enantioselective construction
phytotoxins solanapyrones D (1) and E (2) have been synthesized from the decalone prepared by the domino Michaelreaction of the kinetic enolate of optically pure acetylcyclohexene with methylcrotonate. The decalone was transformed into a solanapyrone core by equilibration into thermodynamically stable trans-decalone (11), dehydroxylation, and dehydration. Condensation of a methyl acetoacetate equivalent