Trimethyl-(5E)-5-pentadecen-1-ynyl-silane is an intermediate in the synthesis of (4E, 8E)-Sphingadienine-C18-1-phosphate (S680680), which is an analogue of (4E, 14Z)-Sphingadienine-C18 (S680630), a sphingoid base of sea cucumber cerebroside that may have cytotoxicity activity against human colon cancer cells.