cosmo
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Question about synthesis of halo-substituted aryl Grignards
Hey there,
I had a quick question about the synthesis of halogenated Grignard reagents. Suppose I took some 1-bromo-4-fluorobenzene, or 1-chloro-4-fluorobenzene.
Would the reaction between one of these and Mg turnings in ether with a small amount of I2 as a catalyst to get things going proceed as I'm thinking
it would yielding 4-fluorophenyl magnesium bromide (or 4-fluorophenyl magnesium chloride), or would something else happen? I was of the understanding
that fluorine does not like to participate in the Grignard... bromine and chlorine only.
Am I right in saying this, or am I way off base here? Any help much appreciated. Thanks.
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Picric-A
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The reaction would proceed with the bette leaving group (ie, I>Br>Cl>F). You would have to use stoichiometric amounts of Mg though to ensure
that the other halogen isnt touched.
Generally RMgF grignards are petty hard to make and s you would struggle to make it b accident. even RMgCl can be a challenge to make ( chlorobenzene
is hard to react with Mg)
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cosmo
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Very helpful, thanks!
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