1126650-30-3Relevant academic research and scientific papers
Hydrogallation reactions involving the monoalkynes H5C 6-C≡C-SiMe3 and H5C6- C≡C-CMe3 - cis/trans isomerisation and substituent exchange
Uhl, Werner,Claesener, Michael,Haddadpour, Sima,Jasper, Beate,Tiesmeyer, Ines,Zemke, Sarina
, p. 2889 - 2896 (2009/05/30)
Phenyl-trimethylsilylethyne, H5C6-C≡C-SiMe 3, reacted with different dialkylgallium hydrides, R2Ga-H (R = Me, Et, nPr, iPr, tBu), by the addition of one Ga-H bond to its C≡C triple bond (hydrogallation). The gallium atoms attacked selectively those carbon atoms, which were also attached to trimethylsilyl groups. The cis arrangement of Ga and H across the resulting C=C double bonds resulted only for the sterically most shielded di(tert-butyl)-gallium derivative, while in all other cases spontaneous cis/trans rearrangement occurred with the quantitative formation of the trans addition products. The diethyl compound Et 2Ga-C(SiMe3)= C(H)-C6H5 (2) gave by substituent exchange the secondary prod-ucts EtGa[C(SiMe3)=C(H)- C6H5]2 (7, Z,Z) and Ga[C(SiMe3)= C(H)-C6H5]3 (8). Interestingly, compound 8 has two alkenyl groups with a Z configuration, while the third C=C double bond has the cis arrangement of Ga and H (E configuration). The reversibility of the cis/trans isomerisation of hydrogallation products was observed for the first time. tert-Butyl-phenylethyne gave the simple addition product, R 2Ga(C6H5)=C(H)-CMe3 (9), only with di(n-propyl)gallium hydride.
