1: C10H14BClN2 With magnesium bis(2,2,6,6-tetramethylpiperamide) in tetrahydro-4H-pyran; hexane RefluxCoolingInert atmosphere; 2: With iodine in tetrahydro-4H-pyran; hexane T=20°C; Inert atmosphereCooling; 3: 2,3-dimethylbutane-2,3-diol Further stages;