Stereoselective synthesis of the dihydrobenzo[b]furan segments of the ephedradine alkaloids
Abstract
Syntheses of dihydrobenzofuran derivatives have involved formation of phenol substituted β-hydroxy esters by an aldol reaction followed by Lewis-acid-catalysed intramolecular cyclisation as key steps; the use of chiral oxazolidinones in the aldol reaction has formed the basis of enantionspecific syntheses.