Increased Activity of in Situ Catalysts for Alkyne Metathesis
摘要:
[GRAPHIC]Reaction of an enyne (1,1-diphenyl-pent-1-ene-3-yne) with a preheated mixture of Mo(CO)(6)/4-chlorophenol/3-hexyne at 130 degreesC furnished 1,1,6,6-tetraphenylhex-1,5-diene-3-yne in an 80% yield. If the starting material was heated with a mixture Of MO(CO)6 and 4-chlorophenol under identical conditions, no reaction was observed.
The present invention provides heterogeneous organometallic catalysts for alkyne metathesis, including the metathesis of internal alkynes. Organometallic precursors are covalently bonded to the oxygen atoms of metal oxide supports to form catalysts having carbyne functionality. The heterogeneous catalysts provide improved turn-over frequencies at lower reaction temperatures than conventional catalysts.
A Mo(VI) Alkylidyne Complex with Polyhedral Oligomeric Silsesquioxane Ligands: Homogeneous Analogue of a Silica-Supported Alkyne Metathesis Catalyst
作者:Hyeon Mo Cho、Haim Weissman、Scott R. Wilson、Jeffrey S. Moore
DOI:10.1021/ja065101x
日期:2006.11.1
A highly active alkyne metathesis catalyst is realized by replacing the amide ligands of a molybdenum(VI) trisamide alkylidyne complex with silanol groups from incompletely condensed POSS (polyhedral oligomeric silsesquioxane) ligands. This catalyst serves as an effective homogeneous mimic of an amorphous silica-supported catalyst. Reactivities of various catalytic mixtures are reported along with an X-ray structure of the aniline-coordinated amidodisiloxymolybdenum(VI) alkylidyne complex.
Increased Activity of in Situ Catalysts for Alkyne Metathesis
作者:Glen Brizius、Uwe H. F. Bunz
DOI:10.1021/ol026118x
日期:2002.8.1
[GRAPHIC]Reaction of an enyne (1,1-diphenyl-pent-1-ene-3-yne) with a preheated mixture of Mo(CO)(6)/4-chlorophenol/3-hexyne at 130 degreesC furnished 1,1,6,6-tetraphenylhex-1,5-diene-3-yne in an 80% yield. If the starting material was heated with a mixture Of MO(CO)6 and 4-chlorophenol under identical conditions, no reaction was observed.
Synthetic Applications with Use of a Silica-Supported Alkyne Metathesis Catalyst
作者:Hyeon Mo Cho、Haim Weissman、Jeffrey S. Moore
DOI:10.1021/jo8003919
日期:2008.6.1
A highly active and durable fumed silica-supported heterogeneous molybdenum(VI) catalyst was applied to ring closing alkyne metathesis and cyclooligomerization reactions to give high yields of metathesis products near room temperature conditions.