Rhodium-catalyzed anti selective cross-addition of bis(trimethylsilyl)acetylene to diarylacetylenes via carbon-silicon bond cleavage

The addition of bis(trimethylsilyl)acetylene to diarylacetylenes proceeds efficiently and selectively in a formal anti fashion in the presence of Rh(OH)(cod)]2/bisphosphine and phenol as catalyst and activator, respectively, accompanied by cleavage of one of the C-Si bonds to produce the corresponding (Z)-enynes. The products can further couple with the same or a different diarylacetylene molecule to give rise to (Z,Z)-1,2,5,6-tetraaryl-1,5-hexadien-3-ynes that show relatively strong solid-state fluorescence.