# Why does the Grignard reagent of CH3I can only be prepared using diethyl ether as solvent but there is no reaction when using THF?

Does anyone know why Grignard reagent of CH3I can only be prepared using diethyl ether as a solvent and yields no reaction when developed in THF? Theoretically, I is the most reactive halogen for Grignard reactions, so using THF or diethyl ether should make no difference.

• Can you provide a reference for this? I have never heard of this problem. – bon Jun 7 '16 at 21:21
• It was something my lab teacher said. He tried several times doing the reaction in THF but it didn´t work. – Juan Manuel Perez Bertoldi Jun 9 '16 at 1:06

• It seems like $\ce{MgI2}$ should be equally sparingly soluble in diethyl ether. Do you have a reference for your solubility claim? – Ben Norris Jun 8 '16 at 0:59