| 词条 | Alkyne metathesis |
| 释义 |
HistoryThe Mortreux system consists of the molybdenum catalyst molybdenum hexacarbonyl Mo(CO)6 and resorcinol cocatalyst. In 1975 T.J. Katz proposed a metal carbyne and a metallacyclobutadiene as an intermediate and in 1981 R.R. Schrock characterized several metallacyclobutadiene complexes that were catalytically active. The Schrock catalyst system tris(t-butoxy)(2,2-dimethylpropylidyne)tungsten(VI) is unreactive towards alkenes.[3] On the other hand, Fischer carbenes have no value in alkyne or alkene metathesis. The Schrock catalyst is commercially available and is prepared by amidation of tungsten tetrachloride with lithium dimethylamide to a W2(NMe2)6 which undergoes alcoholysis by tert-butoxy groups with tert-butanol. This alkylidyne complex undergoes a metathesis with neoheptyne to give the final product. In 2001, Fürstner reported a new molybdenum catalyst replacing alkoxide with aniline ligands.[4] Ring closing alkyne metathesisAlkyne metathesis can be used in ring-closing operations and RCAM stands for ring closing alkyne metathesis. The olfactory molecule civetone can be synthesised from a di-alkyne. After ring closure the new triple bond is stereoselectively reduced with hydrogen and the Lindlar catalyst in order to obtain the Z-alkene (cyclic E-alkenes are available through the Birch reduction). An important driving force for this type of reaction is the expulsion of small gaseous molecules such as acetylene or 2-butyne. The same two-step procedure was used in the synthesis of the naturally occurring cyclophane turriane. Trisamidomolybdenum(VI) alkylidyne complexes catalyze alkyne metathesis.[5] Nitrile-alkyne cross-metathesisBy replacing a tungsten alkylidyne by a tungsten nitride and introducing a nitrile Nitrile-Alkyne Cross-Metathesis or NACM couples two nitrile groups together to a new alkyne. Nitrogen is collected by use of a sacrificial alkyne (elemental N2 is not formed):[6][7] References1. ^{{cite journal |title= Alkyne metathesis |author= Fürstner, A. |author2= Davies, P. W. |journal= Chemical Communications |year= 2005 |issue= 18 |pages= 2307–2320 |doi= 10.1039/b419143a|pmid= 15877114 }} 2. ^{{cite journal |title= Mo[N(t-Bu)(Ar)]3 Complexes As Catalyst Precursors: In Situ Activation and Application to Metathesis Reactions of Alkynes and Diynes |author= Fürstner, A. |author2= Mathes, C. |author3= Lehmann, C. W. |journal= J. Am. Chem. Soc. |year= 1999 |volume= 121 |issue= 40 |pages= 9453–9454 |doi= 10.1021/ja991340r|hdl= 11858/00-001M-0000-0024-1DF5-F }} 3. ^{{cite journal |title= Tungsten(VI) neopentylidyne complexes |author= Schrock, R. R. |author2= Clark, D. N. |author3= Sancho, J. |author4= Wengrovius, J. H. |author5= Rocklage, S. M. |author6= Pedersen, S. F. |journal= Organometallics |year= 1982 |volume= 1 |issue= 12 |pages= 1645–1651 |doi= 10.1021/om00072a|doi-broken-date= 2019-02-16 }} 4. ^{{cite journal |title= Metathesis of alkynes by a molybdenum hexacarbonyl–resorcinol catalyst |journal= Chemical Communications |year= 1974 |issue= 19 |pages= 786–787 |doi= 10.1039/C39740000786 |first=Andre |last=Mortreux}} 5. ^{{cite journal|title=Preparation of a Trisamidomolybdenum(VI) Propylidyne Complex|authors=Wei Zhang, Yunyi Lu, Jeffrey S. Moore|journal=Org. Synth.|year=2007|volume=84|page=163|doi=10.15227/orgsyn.084.0163}}{{cite journal|title=Preparation of a Carbazole-Based Macrocycle via Precipitation-driven Alkyne Metathesis|authors=Wei Zhang, Hyeon Mo Cho, Jeffrey S. Moore|journal=Org. Synth.|year=2007|volume=84|page=177|doi=10.15227/orgsyn.084.0177}} 6. ^{{cite journal |title= Catalytic Nitrile-Alkyne Cross-Metathesis |author= Geyer, A. M. |author2= Gdula, R. K. |author3= Wiedner, E. S. |author4= Johnson, M. J. A. |journal= J. Am. Chem. Soc. |year= 2007 |volume= 129 |issue= 13 |pages= 3800–3801 |doi= 10.1021/ja0693439|pmid= 17355136 }} 7. ^{{cite news |title= Nitrile-Alkyne Cross-Metathesis |author= Ritter, S. |date= March 26, 2007 |work= Chemical & Engineering News |url= http://pubs.acs.org/cen/news/85/i13/8513notw7.html }} External links
1 : Carbon-carbon bond forming reactions |
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