Wednesday, April 22, 2020

REFORMATSKY REACTION

Reformatsky Reaction





The formation of ester-stabilized organozinc reagents and their addition to carbonyl compounds



Mechanism of the Reformatsky Reaction



Organozinc compounds are prepared from α-halogenesters in the same manner as Grignard Reagents. This reaction is possible due to the stability of esters against organozincs. Due to the very low basicity of zinc enolates, there is hardly any competition from proton transfer, and the scope of carbonyl addition partners is quite broad. In presence of ketones or aldehydes, the organozinc compounds react as the nucleophilic partner in an addition to give β-hydroxy esters.





An ester-stabilized organozinc reagent
Compared to organolithiums and organomagnesium halides (Grignard reagents), the organozinc halide reagents used in the Reformatsky Reaction are relatively stable, and many are available commercially.


Recent Literature





An operationally simple and very efficient Reformatsky reaction of aldehydes has been carried out in THF in the presence of low valent iron or copper which were prepared in situ employing a bimetal redox strategy through reduction of Fe(III) or Cu(II) salts with magnesium.




Titanocene(III)-Promoted Reformatsky Additions




Iron(0)-Mediated Reformatsky Reaction for the Synthesis of β-Hydroxyl Carbonyl Compounds




The Synthesis of Medium-Chain-Length β-Hydroxy Esters via the Reformatsky Reaction





Bisoxazolidine-Catalyzed Enantioselective Reformatsky Reaction




In- or In(I)-Employed Tailoring of the Stereogenic Centers in the Reformatsky-Type Reactions of Simple Ketones, α-Alkoxy Ketones, and β-Keto Esters




Double Reformatsky Reaction: Divergent Synthesis of δ-Hydroxy-β-ketoesters




Efficient Synthesis of 2-Amino Acid by Homologation of β2-Amino Acids Involving the Reformatsky Reaction and Mannich-Type Imminium Electrophile




High Chelation Control of Three Contiguous Stereogenic Centers in the Reformatsky Reactions of Indium Enolates with α-Hydroxy Ketones: Unexpected Stereochemistry of Lactone Formation

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