Alkyl-, alkoxy-, and aryloxy-substituted conjugated enynes 1 in the presence of Pd (PPh3) 4 catalyst smoothly underwent the regiospecific [4+ 2] cycloaddition reaction with conjugated alkyl-and alkoxy-substituted symmetric diynes 2 to give multisubstituted aryl ethers 3 in good to high yields. Benzannulation of enynes 1d-g with unsymmetric diyne 6, possessing alkyl and alkoxy groups at acetylenic terminii, in most cases produced an aromatic product 8 ...
