Reformatsky type additions of haloacetonitriles to aldehydes mediated by metallic nickel

Cu2O-catalyzed selective 1,2-addition of acetonitrile to α,β-unsaturated aldehydes

A cyanomethylation of α,β-unsaturated aldehydes with acetonitrile as a nucleophile is disclosed. The reaction is promoted with Cu₂O as an inexpensive catalyst. Mild conditions are used, and the reaction completes within a few minutes.

Zinc-mediated Addition of Bromoacetonitrile to Carbonyl Compounds under Solvent-free Conditions

Zinc mediated addition reaction of bromoacetonitrile with aryl aldehydes and ketones produces β-hydroxynitriles under solvent-free conditions. The valuable feature of the methodology are solvent-free and catalyst-free conditions and short reaction times (5 min).

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

[reactions: see text] Comprehensive studies were carried out on efficient In- or In(I)-based diastereoselective Reformatsky-type reactions of simple ketones, alpha-alkoxy ketones, and beta-keto esters. High anti selectivity was established in the addition of the branched alpha-halo ester derivatives to simple ketones using indium metal under THF-refluxing conditions. The stereochemistry undoubtedly indicated that the involvement of a cyclic transition state, formed from the ketone and stereochemically preferred transient E-enolate derived from the branched alpha-halo ester. Next, with the view of tailoring high degree of stereoselection, the concept of chelation-controlled addition of indium enolates was envisioned. In this line, marvelously syn selective additions to alpha-alkoxy ketones and beta-keto esters were established. Interestingly, these diastereoselective additions to alpha-alkoxy ketones and beta-keto esters require either In(I)X or In-InCl3 systems in toluene under ultrasonication, while very poor efficiency and diastereoselectivity were obtained using indium metal or THF as solvent. The stereochemistry of key products was unambiguously determined by the single-crystal X-ray structure analyses. On the basis of the observed astonishing diastereoselectivities due to strong chelation plausibly, a low-valent RIn(I)-type transient spices could be projected as very reactive spices in the Reformatsky-type reactions.

In- or In(I)-Employed Diastereoselective Reformatsky-Type Reactions with Ketones: 1H NMR Investigations on the Active Species

An efficient In- or In(I)-based stereoselective C-C bond formation is reported; the diastereoselective Reformatsky-type reactions of ketones. The predominant formations of anti isomers, confirmed by the X-ray structure analyses of ester derivatives of respective alcohols 9a(1)() and 13a(1)(), conclusively revealed the stereochemistry of the reaction path. (1)H NMR investigations revealed the formation of two types of alpha-metalated transient species from alpha-halo esters with In or In(I) halides. [reaction: see text]

Rhodium-catalyzed reformatsky-type reaction

A novel Reformatsky-type reaction was developed using RhCl(PPh(3))(3) and diethylzinc. Inter- and intramolecular Reformatsky-type reactions were achieved efficiently under mild reaction conditions to give beta-hydroxy esters.

Tin-mediated Organic Reactions: A Practical Method for the Synthesis of β-Hydroxynitriles and β-Hydroxyketones

In the presence of chlorotrimethylsilane, the tin mediated addition of bromoacetonitrile or α-bromacetophenone to aldehydes in THF gives β-hydroxynitriles or β-hydroxyketones in moderate to good yields.