THE PALLADIUM -TRIBUTYL FORMATE REAGENT IN THE STEREOSELECTIVE HYDROGENATION, AND STEREO- AND REGIOSELECTIVE HYDROARYLATION OF ALKYL 4-HYDROXY-2-ALKYNOATES: A ROUTE TO SUBSTITUTED BUTENOLIDES

Article abstract of DOI:10.1016/S0040-4020(01)85839-7

The reaction of aryl iodides with alkyl 4-hydroxy-2-alkynoates in the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst provides a convenient route to functionalized substituted butenolides through a one pot hydroarylation/cyclization reaction.In the presence of formic acid, tri-n-butylamine and a palladium(II) catalyst, alkyl 4-hydroxy-2-alkynoates undergo a one pot hydrogenation/cyclization reaction to the butenolide ring.By increasing the excess of formic acid, direct formation of saturated γ-lactones can be observed.Reaction occur with high stereoselectivity and, in the case of the hydroarylation, with goog regioselectivity.