Three stable 1-silapropadienes

Three stable 1-silapropadienes, 1, 6 and 7, were prepared by reactions betw een fluoroalkynylsilanes bearing bulky substituents on silicon and organoli thium reagents. Under acid catalysis 6 underwent intramolecular insertion o f the Si=C double bond into an adjoining C-H bond, yielding 15. A different C-H insertion by the Si=C double bond occurred for silapropadiene 7, givin g 19. X-ray crystal structures are presented for 15, 19, 16, a product of p hotorearrangement of 6, and 17, a fluoroalkynylenesilane precursor to 7.