Rhodium-Catalyzed [2 + 2 + 2] Cyclizations of 1,6-Enynes.

Abstract Various terminal alkynes in the presence of 5 mol% of RhCl(PPh 3 ) 3 were homo-coupled to the conjugated enynes. 1,6-Enynes in the presence of 5 mol% RhCl(PPh 3 ) 3 and 10 mol% Ag(I) salts underwent [2+2+2]-cyclization among two triple bonds and one pendant double bond in good to excellent yields.