video tutorial Extreme Grignard reagents -- how wet can you get

Summary

• Goal: assess how dry Grignard reactions must be and whether amateur dry conditions are viable.
• Experiment 1 (dry flask, non-dried ether, non-dried Mg): 1 g Mg, 10 ml ether, iodine, methyl iodide; reaction started slowly (took ~45 minutes total); conclusion: the reaction requires dry conditions, but Mg quality strongly influences speed; some tolerance to dryness.
• Experiment 2 (fully dried ether with sodium-dried drying): same procedure; reaction initiated sooner and completed in about 15 minutes; conclusion: with high-quality drying and ether, Grignards proceed faster; moisture control remains important.
• Experiment 3 (dichloromethane dried with phosphorus pentoxide): no reaction after two hours; conclusion: Grignards do not readily form in dried DCM; ether + calcium chloride drying agent and good Mg are preferable; high-quality Mg helps, but patience can compensate for lower-quality turnings; ensure proper ether handling and ventilation.
• Overall takeaway: Grignard reactions can work under dry amateur conditions given reagent-quality ether, appropriate drying agents, and decent magnesium; solvent choice and Mg quality significantly affect rate; with precautions, low-quality Mg can still be used.