Water reaction with Grignards

Synthetic applications requiring water-free conditions, such as reactions with Grignard reagents, aryl and alkyl aluminum... 

Ferrocene is easily prepared by the direct reaction process or by a reaction with Grignard reagents as shown in eqs. (15.2) and (15.5). Keal and Pauson [9] and Miller [8] found that ferrocene is stable in water, 10% NaOH aqueous solution, and concentrated hydrochloride acid at around the boiling point. It sublimates at 100 "C without decomposition and is stable up to 470 °C under a nitrogen atmosphere. It dissolves in organic solvents such as alcohol, ether and benzene. As a solid and a solution it is stable in air [8,9,25]. 

Preparation of Isocyanates. Isocyanates are prepared by rearrang-ii azides in inert solvents such as ethers, chloroform, benzene and its homologs, malonic ester, mid ligroin. If the isocyanate is to be isolated, the solvent is removed by distillation, or, if the isocyanate is the lower boiling, it is distilled directly. In this operation, a safety shield is advisable to guard against a possible explosion of yet undecomposed azide. Isocyanates can be converted to sym-ureas by reaction with water, to urethans by reaction with alcohols, to os-ureas by reaction with amines, or to acylamines by reaction with anhydrous acids or acid anhydrides, or they can be hydrolyzed directly to amines. Acylamines can also be obtained. from isocyanates by reaction with Grignard re-... 

The reaction with a carbonyl substrate 3 is similar to a Grignard reaction. Hydrolytic workup then yields the /3-hydroxy ester 4. Sometimes product 4 easily eliminates water to yield directly an o ,/3-unsaturated ester. 

The reactions of Grignard reagents with water and alcohols are simply acid-base reactions => the Grignard reagent behaves as if it contained an carbanion. 

Indeed, it is endothermic by over 130 kJmoU This documents that the polar/ionic bond between magnesium and oxygen is exceptionally strong, a fact we already surmised by the vigor of the reaction of Grignard reagents with air and water. 

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