1-Bromo-2,6-Bis(chloromagnesiomethyl)benzene From the Attempted Synthesis of a Doubly Benzylic 1,3,5-Tri-Grignard Reagent

Abstract

The reaction of the trihalide 1 -bromo-2,6-bis(chloromethy 1 )benzi>ne (5) with magnesium in THF was performed in order to produce the corresponding tri-Grignard reagent 4. However, contrary to expectation, the reaction proceeded only partially. Transformation of the two benzylic chloride functions gave rise to the formation of the di-Grignard reagent 6 which was charactenzed by derivatization to the corresponding bis(trimethyltin) derivative 7. The aromatic bromide functionality turned out to be unreactive, both in 5 and in 7. Presumably, this is caused by steric hindrance.