Preparation of Functionalized Diorganomagnesium Reagents in Toluene via Bromine or Iodine/Magnesium-Exchange Reactions

Alexandre Desaintjean; Fanny Danton; Paul Knochel

doi:10.1055/a-1551-4093

Synthesis, Table of Contents

Synthesis 2021; 53(23): 4461-4476
DOI: 10.1055/a-1551-4093

paper

Preparation of Functionalized Diorganomagnesium Reagents in Toluene via Bromine or Iodine/Magnesium-Exchange Reactions

Alexandre Desaintjean‡

,

Fanny Danton‡

,

Paul Knochel ∗

Abstract

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Abstract

A wide range of polyfunctionalized di(hetero)aryl- and dialkenyl-magnesium reagents are prepared in toluene within 10 to 120 minutes between –78 °C and 25 °C via an I/Mg- or Br/Mg-exchange reaction using reagents of the general formula R₂Mg (R = sBu, Mes). Highly sensitive functional groups, such as triazene or nitro, are tolerated in these exchange reactions, enabling the synthesis of various functionalized (hetero)arene and alkene derivatives after quenching with several electrophiles including allyl bromides, acyl chlorides, aldehydes, ketones, and aryl iodides.

Key words

alkenes - apolar solvents - arenes - Grignard reaction - halogen/magnesium-exchange - heterocycles - magnesium

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References

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When used in association with R₂Mg (1c, R = sBu; 1d, R = Mes), DMPU increases the exchange rate, thus improving conversions and diminishing side reactions:

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Supplementary Material

Supporting Information