An enyne metathesis is an organic reaction taking place between an alkyne and an alkene with a metal carbene catalyst forming a butadiene. This reaction is a variation of olefin metathesis.[1]
The general scheme is given by scheme 1:
When the reaction is intramolecular (in an enyne) it is called ring-closing enyne metathesis or RCEYM (scheme 2):
with Y representing oxygen or nitrogen and n an integer.
The reaction was first described in 1985 with the conversion of biphenyl 3.1 to a phenanthrene in scheme 3:[2]
The carbene is a tungsten carbonyl when used in stoichiometric amounts (1 equivalent) yields 41% of the phenanthrene 3.2 and when used in catalytic amounts phenanthrene 3.3. The stereoselectivity of this reaction is large with the metal atom exclusively adding to one of the alkyne carbon atoms in the initial reaction step.
- ^ Diver, Steven T.; Anthony J. Giessert (March 2004). "Enyne Metathesis (Enyne Bond Reorganization)". Chemical Reviews. 104 (3): 1317–1382. doi:10.1021/cr020009e. PMID 15008625.)
- ^ Katz, Thomas J.; Timothy M. Sivavec (February 1985). "Metal-catalyzed rearrangement of alkene-alkynes and the stereochemistry of metallacyclobutene ring opening". Journal of the American Chemical Society. 107 (3): 737–738. doi:10.1021/ja00289a054. Archived from the original on September 24, 2017. Retrieved 2008-12-06.