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

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

Publication History

Received: 01 July 2021

Accepted after revision: 15 July 2021

Accepted Manuscript online:
15 July 2021

Article published online:
04 August 2021

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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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