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A THF solution of MesMgBr.LiCl is first prepared by an adaptation the procedure of Knochel et al. To a stirred suspension of magnesium turnings (0.72 g, 30 mmol) and anhydrous LiCl (1.26 g, 30 mmol) in anhydrous THF (40 mL) is added 2-bromomesitylene (5.05 mL, 33 mmol). The exothermic reaction initiates slowly and is allowed to stir overnight at room temperature. To the resulting mixture, which is cooled to 0° C., is added 2-azidomesitylene (4.59 g, 28.5 mmol). Stirring is continued for 1 hour at 0° C., and then an additional 1 hour while allowing to warm to room temperature. The reaction mixture is quenched by pouring the contents into water. A minimum of aqueous NH4Cl is added to neutralize the pH, and the organic products are extracted with Et2O. After washing the combined organic layers with brine, solvents are evaporated at room temperature under reduced pressure to afford a crude product that is recrystallized from Et2O-MeOH to afford 8b (7.41 g, 92%) as off-white needles over 2 crops. 1H-NMR (CDCl3, 300 MHz): δ=9.14 (br s, 1H), 6.93 (br s, 4H), 2.32-2.30 (br m, 18H). M.p.: 92-94° C. (dec). Characterization data for 8b are consistent with literature values.

1. customThe exothermic reaction initiates slowly
2. temperatureTo the resulting mixture, which is cooled to 0° C.
3. stirringStirring
4. waitis continued for 1 hour at 0° C.
5. customan additional 1 hour
6. temperatureto warm to room temperature
7. customThe reaction mixture is quenched
8. additionby pouring the contents into water
9. additionA minimum of aqueous NH4Cl is added
10. extractionthe organic products are extracted with Et2O
11. washAfter washing the combined organic layers with brine, solvents
12. customare evaporated at room temperature under reduced pressure
13. customto afford a crude product that
14. customis recrystallized from Et2O-MeOH