Iodine → OcH-BINAP

Participants

Reaction Conditions

Reaction Steps

Into a 1-liter four-necked flask was placed 4.26 g (0.177 mole) of magnesium. After nitrogen replacement, a small amount of iodine and 20 ml of dry tetrahydrofuran were added in this order. Thereto was then added 0.6 ml of 1,2-dibromoethane using a syringe. To the mixture in the flask, a solution separately prepared by dissolving 32.5 g (0.0774 mole) of 2,2'-dibromo-5,5',6,6',7,7',8,8'-octahydro-1,1,-binaphthyl (IV) in a mixed solvent of 330 ml of toluene and 90 ml of tetrahydrofuran was added dropwise from a dropping funnel over a period of 7 hours. During this addition, the temperature of the reaction mixture was 80° to 90° C. After the addition of the compound (IV) solution, stirring was further continued at 94° C. for 19 hours. The resulting reaction mixture was cooled to 5° C., and 34.27 g (0.148 mole) of diphenylphosphinic chloride was added thereto dropwise over a period of 30 minutes. The reaction mixture was then heated to 72° C., stirred at this temperature for 3.5 hours, and then cooled to room temperature. Thereafter, 100 ml of water was added thereto, and the resulting mixture was heated to 80° C., stirred at this temperature for 20 minutes, cooled to room temperature, and then allowed to stand for a night, whereby a white solid was deposited. This solid was collected by filtration, washed twice with 100 ml of water, further washed with 100 ml of a hexane-toluene (9:1 by volume) mixture, and then dried under a reduced pressure (0.1 mmHg) at 70° C. for 7 hours, thereby obtaining 32.8 g of the titled compound (VI).

Provenance & Evidence