Nicolas Tesson, Sandrine Deshayes
Feb 1, 2000
Citations
0
Influential Citations
3
Citations
Journal
Organic Preparations and Procedures International
Abstract
Ethyl I ,3-cyclohexadien-1 -carboxylate (4) has often been used in Diels-Alder reactions with various dienophiles to build 1 ,Cdisubstituted bicyclo[2.2.2] octanes,' to synthesize aromatic esters (by cycloaddition to alkynes followed by aromatization of adducts)2 and to prepare molecules of biological interest such as tabtoxin (the exotoxin from Pseudomonus fabaci)3 and sirenin (a female sexual pheromone of the aquatic fungus, Allomyces)! The critical step in the synthesis of 4 originally described by Hunig and Kahanek" and modified by Grob et al.,b is the preparation of the dienamine 2 in good yield as extensive polymerization occurs during distillation. The major drawbacks for this synthesis are long reaction times (15 days), the use of toxic solvents (benzene), multiple distillations, and poor reproductibility with an optimal yield of 30%. This article describes an improved procedure for the synthesis of compound 4 employing microwave activation coupled with dry media techniques, which are known to give rapid, clean and economical reactions in improved yields.'