Synthesis of Alkynes Composed of the Novel Substituents and Their Reactions with B(C6F5)3

Five alkyne compounds of varied novel substituents as Mes(2)HSiC (1, Mes=2,4,6-Me3C6H2), MuC(NAr)(2)]GeC -:-CPh (2, IAr=2,6-Pr2C6H3), [PhC(N(13)u)(2)]SnC CPPh2 (3), [HC(CIVIe)2(1\TAr)21SnC-CPPh2, (4) and [HC(CMe)(2)(NAr)2]ZnC --CPPh2 (5) have been synthesized. Compounds 1 and 2 reacted with B(C6F5)3 by the 1,1-carboboration to give compounds (PhXMes(2)HSOC=C(C6F5)B(C6F5)(2) (6) and [(BuC)-Bu-r(NAr)(2)]Gel(Ph)C=C(C6F5)B(C6F5)(2). (7), respectively, where (F5C6)3B/Mes(2)HSi group exchange was suggested to occur initially for the former reaction while the (F5C6)(3)B/ rBuC(NAr)(21)Ge exchange was for the latter one. Compound 6 is a acyclic alkene whereas 7 is viewed as a germanaboracyclobutene owing to a strong Gell >B donor-acceptor bonding being a Gen/B frustrated Lewis pair (FLP). Compounds 3-5 reacted with B(C6F5)(3) to undergo a ligand coordinated metal group/B(C6F5)(3) exchange followed by bonding of metal group at PPh2, resulting in the formation of a novel type of intramolecular zwitterionic alkynes [PhC((NBu)-Bu-t)(2)]SnP(Ph-2)C CB(C6F5)(3) (8), [HC(CMe)(2)(NAr)(2)]SnP(Ph-2)C CB(C6F5)(3) (9), and [FIC(CMe)(2)(NAr)(2)]ZnP(Ph-2)C C-13(C6F5)(3) (10), respectively. Compounds 1.10 have been characterized by spectroscopy and elemental analysis, of which 4, 6, 7, land 10 are further authenticated by X-ray crystallography. The mechanisms of these reactions are discussed.