Blaise Ketone Synthesis on:
[Wikipedia]
[Google]
[Amazon]
The Blaise ketone synthesis (named after Edmond Blaise) is the
After the oxygen forms a bond with the organozinc compound, R’ shifts to the carbonyl carbon, having chlorine act as a leaving group and removing the negative charge from zinc. The chlorine that left returns to form a bond with zinc, pushing the electrons back on to oxygen and thus forming the ketone.
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
of acid chloride
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...
s with organozinc compound
Organozinc compounds in organic chemistry contain carbon (C) to zinc (Zn) chemical bonds. Organozinc chemistry is the science of organozinc compounds describing their physical properties, synthesis and reactions.The Chemistry of Organozinc Compoun ...
s to give ketones.
The reaction was claimed to bring excellent yields by Blaise, however, investigators failed to obtain better than moderate yields (50%). Thus, the reaction is particularly ineffective in forming ketones from acyl chlorides.
The reaction also works with organocuprates.
Reviews have been written.
Reaction Mechanism
The mechanism is sampled from the proposed mechanism fororganocadmium compound
An organocadmium compound is an organometallic compound containing a carbon to cadmium chemical bond. Organocadmium chemistry describes physical properties, synthesis, reactions and use of these compounds. Cadmium shares group 12 with zinc and me ...
s, given that the mechanisms are identical to one another the proposed mechanism for the reaction is the same as the one for organocadmium compounds.
After the oxygen forms a bond with the organozinc compound, R’ shifts to the carbonyl carbon, having chlorine act as a leaving group and removing the negative charge from zinc. The chlorine that left returns to form a bond with zinc, pushing the electrons back on to oxygen and thus forming the ketone.
Variations
Blaise-Maire reaction
The Blaise-Maire reaction is the Blaise ketone synthesis using β-hydroxy acid chlorides to give β-hydroxyketones, which are converted into α,β-unsaturated ketones usingsulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
.
Ketone Formation from Organocadmium Compounds
This ketone formation is an identical reaction to the Blaise ketone synthesis. Only instead of organozinc compounds, organocadmium compounds are used and produce higher yields.See also
*Blaise reaction
The Blaise reaction is an organic reaction that forms a β-ketoester from the reaction of zinc metal with a α-bromoester and a nitrile. The reaction was first reported by Edmond Blaise (1872–1939) in 1901. The final intermediate is a metaloim ...
*Negishi coupling
The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) specie ...
References
# # # # # # # # # Addition reactions Carbon-carbon bond forming reactions Name reactions Organometallic compounds {{reaction-stub