A general asymmetric synthesis of (-)-.alpha.-dimethylretrodendrin and its diastereomers
摘要:
A Diels-Alder cycloaddition between the fumarate of methyl (R)-mandelate 14 and alpha-hydroxy-alpha'-aryl-o-quinodimethane 12 produced an exo cycloadduct 15 in 44% yield which was converted to optically pure (-)-alpha-dimethylretrodendrin(21) and three of its diastersomers. The 1,2,3-cis diastersomer 19 was found to possess an unexpected conformation as deduced from NOE experiments.