POWERFUL CONTROL BY ORGANORUTHENIUM CATALYSTS OF THE REGIOSELECTIVE ADDITION TO C(1) OR C(2) OF THE PROP-2-YNYL ETHERS C-C TRIPLE BOND

The catalytic activation of pro-2-ynylic ethers HC=CCR2OMe towards car boxylic acids is controlled to regioselectively afford the functional enol esters (RCO2C)-C-1(=CH2)CR2OMe or (RCO2CH)-C-1=CHCR2OMe correspon ding to the addition of the carboxylate to either C(2) or C(1) of the terminal triple bond, depending on the nature of the ruthenium catalys t precursor RuCl2(PPh3)( p-cymene) or Ru(eta(3)-2-methylpropenyl)(2)(d ppe), respectively. (C) 1997 Elsevier Science.