76767-85-6Relevant academic research and scientific papers
New Approach to the Mechanism of the Reaction between Benzyl Grignard Reagents and Carbonyl Compounds
Bernardon, Claude,Deberly, Alain
, p. 463 - 468 (2007/10/02)
The reaction of the magnesium chloride with ketones can lead to the formation of ortho alcohols 4, normal alcohols 3, or enolates.We propose a mechanism for the reaction whose first step, as in the case of aldehydes, is a reversible attack of the ketone at the ortho position of the benzylic Grignard reagent, which can then lead to the formation of the normal alcohol and/or enolate.The fact that benzylmagnesium chloride reacts with cyclobutanone to give a diol analogous to that obtained in reactions with aldehydes, while its reaction with 1,1,1-trifluoro-2-propanone does not give a diol, leads us to propose an interpretation involving steric effects in the rearrangement alkoxide.In the case of ketones, these steric interactions generally prevent the Prins-type reaction leading to diols.
Mechanism of Diol Formation in the Reaction of Benzylic Grignard Reagents with Aldehydes
Bernardon, Claude,Deberly, Alain
, p. 2631 - 2636 (2007/10/02)
2-Hydroxymethyl-1-methylene-1,2-dihydronaphthalene (8) was obtained from the reaction of 1-naphthylmethylmagnesium chloride with monomeric formaldehyde.This compound slowly produces approximately equimolar amounts of 1-methylnaphthalene and 1-(2-hydroxyethyl)-2-hydroxymethylnaphthalene (9) in the presence of MgCl2.In the light of these results and studies on the reactivity of 1-naphthylmethylmagnesium chloride towards acetone and halide-free dibenzylmagnesium towards monomeric formaldehyde, a new mechanism of diol formation in the reaction of benzylmagnesium chloride with aldehydes is described.This mechanism involves an ortho addition on the Grignard reagent, leading to a trienic magnesium alkoxide intermediate (4), which decomposes by a reversible process into Grignard reagent and aldehyde.The latter undergoes a Prins-type reaction with the magnesium alkoxide intermediate in the presence of MgCl2, to give the corresponding diol and toluene.
