Reduction by Grignard reagents

Reduction by Grignard reagents is a very common reaction, was a statement by Kharasch and Weinhouse in their paper [18]. However, Whitmore and George, a few years later, in 1942 [21], in their classic paper on this subject used the following title Abnormal Grignard Reactions. Among others, they reported ... 

The stereochemical course of reduction of imonium salts by Grignard reagents was found to depend on the structure of the reagent 714). Hydro-boration of enamines and oxidation with hydrogen peroxide led to amino-alcohols (7/5). While aluminum hydrogen dichloride reacted with enamines to yield mostly saturated amines and some olefins on hydrolysis, aluminum hydride gave predominantly the unsaturated products 716). 

The reduction of azobenzene by Grignard reagents will be discussed at the end of this section. 

In 1929, Blicke and Powers (9) suggested such electron transfer by Grignard reagents to explain the reduction products encountered with ke-... 

Alkylation of nitroarenes. Nitroarenes are alkylated by Grignard reagents with concomitant reduction of the nitro group in the presence of Cul in catalytic amounts. ... 

Reduction of aryl or vinylic halides. Aryl or vinylic halides are reduced by Grignard reagents in THF in the presence of catalytic amounts of manganese(II) chloride. The choice of solvent is crucial. 

The opening of 9a jlOce -oxides by Grignard reagents (Scheme 74) and the Michael reaction with 17a-ketones (Schemes 104 and 105) have been used to an extremely limited extent. The passage from estrogens to 10-methylsteroids has been effected in low yield by Birch reduction and subsequent reaction with carbenes (Scheme 39). The Reimer—Tiemann reaction has been used for the same purpose [53] with the reaction (70) (71)... 

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