Nozaki–Hiyama–Kishi reaction

The Nozaki - Hiyama -Kishi reaction is a nickel -catalyzed chromium -mediated coupling reaction. In this case, a secondary allyl or vinyl alcohol is formed from an aldehyde and reacting with allyl or vinyl halides. The reaction was published as the first of Tamejiro Hiyama and Nozaki Hitosi in 1977. Here, a chromium (II ) salt solution with benzaldehyde and allyl chloride was implemented.

When comparing this reaction with a Grignard reaction or the addition of organolithium compounds is due to the relatively weak nucleophilicity of the chromium - organyl, much more selective, and are functional groups such as ketones, esters, amides and nitriles tolerated. However, the chrome organyl in terms of HSAB is hard enough to respond with α, β -unsaturated aldehydes 1,2-addition. As the solvent, DMF and DMSO are used because they dissolve the chromium salts well.

Nickel ( II) salts as a catalyst

In 1983 it was observed by the same authors that vinyl halides, vinyl triflates and aryl halides react under similar conditions. 1986 was then determined that a catalytic amount of nickel ( II) chloride accelerates the reaction.

Regardless of Yoshito Kishi came in the same year as part of the palytoxin - total synthesis to the same result.

Palladium acetate also showed good catalytic activity in this reaction.

Reaction mechanism

Nickel is reduced first by the chromium (II) to the element wherein the chromium is oxidized in the oxidation stage III. Followed by oxidative addition of nickel in the carbon-halogen bond to give a Grignard -like compound. After a transmetallation by chromium (III ) creates a nucleophile that can attack the aldehyde.

In the reaction, the amount of nickel catalyst to be kept low in order to avoid side reactions.

Similar reactions are, for example, the Grignard reaction (magnesium ), the Barbier reaction (zinc) or reactions with organolithium reagents.