It is a terminal alkyne. Rhodium-catalyzed asymmetric addition of (triphenylsilyl)acetylene to diphenylphosphinylallene is reported.It may be used in the synthesis of:selenothioic acid S-alkyl esters;methyl 2-(di{ 3, 5-bis[(triphenylsilyl)ethynyl]phenyl}-phosphino)benzoate;2-(di{3,5-bis[(triphenylsilyl)ethynyl]phenyl}-phosphino)benzoic acid. It is a terminal alkyne. Rhodium-catalyzed asymmetric addition of (triphenylsilyl)acetylene to diphenylphosphinylallene is reported. It may be used in the synthesis of:selenothioic acid S-alkyl esters;methyl 2-(di{ 3, 5-bis[(triphenylsilyl)ethynyl]phenyl}-phosphino)benzoate;2-(di{3,5-bis[(triphenylsilyl)ethynyl]phenyl}-phosphino)benzoic acid.