Synthesized mesitylcopper by following the procedure. 

(1) High quality anhydrous solvents (THF/dioxane/Toluene) and good argon or nitrogen protection for all the operations are key to get high yield and quality product, since the mesitylcoppor solution is highly sensitive. 

(2) Less toxic toluene was used to replace bezene for crystallization.

(3) I got more nice crystals from the mother liquid after the 1st crystallization, so keep the mother liquid especially if the yield is not as high.