Metathesis of silylalkynes and cross-metathesis of silylalkyne and 1-alkyne over solid-base catalysts

KF loaded on alumina (KF/Al2O3) catalyzed the metathesis of Me3SiC=CH to Me3SiC=CSiMe3 and HC=CH. The catalytic activity of KF/Al2O3 depended strongly on the heat-pretreatment temperature under vacuum and the loading amount of KF on alumina, An 87% yield of Me3SiC=CSiMe3 was obtained by the reaction of Me3SiC=CH in 30 min at 298 K in the presence of KF/Al2O3 (5 mmol KF/g-Al2O3), which had been pretreated at 673 K for 3 h, KF/Al2O3 also catalyzed the cross-metathesis of Me3SiC=CH and 1-alkynes. When Me3SiC=CH was reacted with PhC=CH in the presence of KF/Al2O3 at 318 K for 2 h, PhC=CSiMe3 was obtained in a 96% yield. The reactions of Me3SiC=CH with tert-BuC=CH and n-BuC=CH gave tert-BuC=CSiMe3 and n-BuC=CSiMe3, respectively, in high yields. (C) 1998 Academic Press.