ENYNE CYCLIZATION METHODOLOGY FOR THE SYNTHESIS OF BIOACTIVE LACTONES

A new methodology for the synthesis of enantiopure natural bioactive l actones from the enyne cyclization of allylic alkynoates under the cat alysis of PdX(2) was developed. For alpha,beta,gamma-trisubstituted bu tyrolactones, the beta,gamma relative stereochemistry can be controlle d by the substituent on the triple bond of the alkynoates and a chiral center is easily introduced from the optically active allylic alcohol s. For alpha,beta-disubstituted lactones, the key intermediate, lacton ic aldehyde, is successfully resolved to both enantiomers via its tart rate acetal derivative.