Di-tert-butyl peroxide → 9-Phenyl-9-Phosphabicyclononane

Participants

Reaction Conditions

Reaction Steps

This procedure is a modification of Mason and Van Winkle's. See U.S. Pat. No. 3,400,163. All glassware is dried at 120° C. and assembled hot under a purge of argon. A 250 mL, 3-neck flask is fitted with magnetic spin bar, thermometer, reflux condenser, a rubber syringe septum, argon inlet, and flowmeter. The reactor system is purged overnight with argon flowing at 3 mL/min., and then charged with redistilled 1,5-cyclooctadiene [43.3 g (49.1 mL), 0.4 mole, density=0.882 g/mL, from Aldrich Chemical Co.] and phenylphosphine [44.0 g (44.0 mL), 0.4 mole, density=1.00 g/mL, from Strem Chemicals] while under a stream of argon. The reaction solution is heated to 135° C. Di-t-butylperoxide [1.46 g (1.8 mL), 0.01 mole, density=0.796 g/mL, from Aldrich Chemical] is mixed with 5 mL of undecane and added with a syringe pump over 1 hour while maintaining the temperature of the exothermic reaction at 135°-145° C. A second portion of di-t-butylperoxide (1.8 mL in 5 mL of undecane) is added rapidly, and the temperature is increased to 150° C. and held for an additional hour. Periodic aliquots, taken with a syringe through the septa, are examined by infrared spectroscopy, and the disappearance of the olefin band at 1645 cm-1 and the P-H band at 2300 cm-1 is monitored. After two hours total reaction time, both of these bands had disappeared. The reaction mixture is distilled through a 6-inch Vigreux column and a mixture, 58.3 g (67%) of 9-phenyl-9-phosphabicyclo[4.2.1]nonane and 9-phenyl-9-phosphabicyclo[3.3.1]nonane, is collected [b.p. 123-125 at 0.1 mmHg], and stored in a refrigerated and septum-sealed flask under a nitrogen gas atmosphere. Reported b.p.: 134°-135° C. at 0.3 mm (Hg). Gas chromatography shows the mixture is 67% 9-phenyl-9-phosphabicyclo[4.2.1]nonane (the earlier eluting isomer) and 33% 9-pheny-9-phosphabicyclo[3.3.1]nonane.

Provenance & Evidence