For your pleasure I just tried the reaction myself but with chlorocyclopropane and m-tolunitrile since I didn't have the other starting materials.
Still a 1M THF solution though. I had to add CuI to get the reaction to start, both for the grignard formation and the alkylation.
Prep:
0.53 Mg turnings (21.8 mmol, 1.1eq) was fused with a small crystal of iodine with a heat gun in a 50mL flat-bottomed RB-flask. 10mL of THF (dried over
mol. sieves) was added and the purple mixture was stirred (pic 1). Chlorocyclopentane (2.08g, 19.89 mmol, 1 eq) was dissolved in 10mL THF and added
dropwise by pipette. After half of it was added and still no reaction had occurred the solution was brought to a boil with a heat gun. The
iodine-color disappeared (pic 2) and the solution became clear but still no sign of the reaction commencing. A very small amount of CuI was added with
the tip of a glass pipette and the reaction started immediately (pic 3). The rest of the chloride was added to keep the mixture refluxing. After it
had finished reacting the whole mixture was again brought to reflux with the help of a heat gun.
m-Tolunitrile (2.25g, 19.20 mmol, 0.97 eq) was dissolved in 5mL THF and was added dropwise by pipette. No reaction occurred even after all the nitrile
had been added. Once again a small amount of CuI was added and the mixture started to violently reflux, almost boiling over (pic 4). After it had
calmed down it was refluxed for 5 minutes and then decanted into 100mL of 1M HCl. The left-over turnings were washed with Et2O 2 times and the
washings decanted into the acid. This was vigorously stirred (pic 5) for 30 minutes and then separated. The aqueos phase was extracted once with Et2O.
The organic phases were combined, dried over MgSO4 and reduced on the rotavap. This gave 3.46g of a golden oil which on TLC (20% EtOAc/pet. Ether)
showed (in descending order) assumed product, starting nitrile, an unknown polar compound and some polymerized stuff that didn't move (pic 6).
The residue was mixed with pet. ether which caused the polymerized stuff to crash out (pic 7). Everything was then ran through a 4 cm silica plug and
the silica eluated with 50mL 20% EtOAc/Pet. ether. This gave a 3.04g of a light yellow oil (pic 8) which was quite pure by TLC (84% yield). A small
band of starting material could still be seen and a faint smell of the nitrile could be noted (pic 9).
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This was all done in less than two hours with no protecting atmosphere and the nitrile could probably be easily removed by distilling the product. Or
just leave it there. I added 1 eq of bromine neat and stirred for 5 minutes and then reduced it on the rotavap. After adding pet. ether and
evaporating it two times together with the excess bromine and HBr I had an orange oil (pic 10) that crashed out as light yellow crystals upon addition
of methanol. Any nitrile that followed from the previous steps can easily be removed here by filtration. (If the 2'-chloro-bromoketone does
crystallize that is, this is 3'-methyl).
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And was needed both in the Grignard formation and the actual coupling.