Stereoselectivities of intramolecular Diels-Alder reactions. Formation of the taxane skeleton
摘要:
The stereodirecting effect of an alkyl (Me) group on the diene and/or dienophile on the intramolecular Diels-Alder reaction leading to the formation of an eight-membered ring has been studied under both thermal and Lewis acid catalyzed cyclization conditions. The synthesis and cycloaddition reactions of tetraenes 2a-d, leading to the formation of the taxane skeleton, is described. Selectivity is shown to vary under thermal conditions depending upon substitution pattern, while the catalyzed cycloaddition invariantly gives the cis-fused product.
Stereoselectivities of intramolecular Diels-Alder reactions. Formation of the taxane skeleton
摘要:
The stereodirecting effect of an alkyl (Me) group on the diene and/or dienophile on the intramolecular Diels-Alder reaction leading to the formation of an eight-membered ring has been studied under both thermal and Lewis acid catalyzed cyclization conditions. The synthesis and cycloaddition reactions of tetraenes 2a-d, leading to the formation of the taxane skeleton, is described. Selectivity is shown to vary under thermal conditions depending upon substitution pattern, while the catalyzed cycloaddition invariantly gives the cis-fused product.