Orbital interactions in the ruthenium olefin metathesis catalysts
If two different ketones are to be coupled, a more complex, indirect method such as the Barton—Kellogg reaction may be used.
The mixture is feedstock and temperature dependent, and separated by fractional distillation. If an E-product is desired, another alternative is the Julia olefinationwhich uses the carbanion generated from a phenyl sulfone.
Z notation has the higher priority groups on "ze zame zide. Frequently, loss of ethene gas is used to drive the reaction towards a desired product. Olefin metathesis Alkenes can be prepared by exchange with other alkenes, in a reaction known as olefin metathesis.
When an alkyl halide is used, the reaction is called a dehydrohalogenation. This is mainly used for the manufacture of small alkenes up to six carbons.
Alkenes with the higher priority groups as determined by CIP rules on the same side of the double bond have these groups together and are designated Z. Olefins comprise a larger collection of cyclic and acyclic alkenes as well as dienes and polyenes.
A titanium compound, Tebbe's reagentis useful for the synthesis of methylene compounds; in this aspirin synthesis polymer formation, even esters and amides react. The Wittig reagent is itself prepared easily from triphenylphosphine and an alkyl halide. Most E2 eliminations start with an alkyl halide or alkyl sulfonate ester such as a tosylate or triflate.