Optically pure ethyl 5-hydroxycyclopent-1-enecarboxylate has been obtained with its acetate in both enantiomeric forms in excellent optical yields from racemic ethyl 5-hydroxycyclopent-1-enecarboxylate by lipase-mediated kinetic resolution. The optically pure (R)-enantiomer thus obtained has been transformed into two naturally occurring iridoid monoterpenes, (+)-mitsugashiwalactone and (-)-dolichodial.
Substitution nucleophile d'acetates de cyclenols allyliques fonctionnels par des organometalliques en presence de sels cuivreux. Application a une synthese rapide de la (±)mitsugashiw alactone
作者:Hassen Amri、Monique Rambaud、Jean Villieras
DOI:10.1016/s0040-4020(01)81522-2
日期:1990.1
Substitution of functional allylic cycloalkenol acetates by Grignardreagents (primary , secondary, tertiary-alkyl, vinyl, aryl) in the presence of a catalytic amount (2.5% equivalent) of cuprous iodide at low temperature, gives high yields of various functional α-substituted cycloalkenes . The reaction can be applied to lithium enolates of esters and need no catalyst, but may be performed with HMPA