PALLADIUM-CATALYZED ALKYL-ALKYL SUZUKI CROSS-COUPLINGS OF PRIMARY ALKYL BROMIDES AT ROOM TEMPERATURE: (13-CHLOROTRIDECYLOXY)TRIETHYLSILANE

A. 1-Bromo-8-chlorooctane (1)An oven-dried, 200-mL, two-necked, round-bottomed flask equipped with an argon inlet and a magnetic stir bar (octagonal, molded pivot ring, 25 mm length and 6 mm diameter) is purged with argon for 5 min and then charged through the open neck with CH 2 Cl 2 (50 mL via syringe) (Note 1), imidazole (2.19 g, 32.1 mmol, 1.10 equiv) (Note 2), and dichlorotriphenylphosphorane (10.4 g, 31.2 mmol, 1.07 equiv) (Note 3).The open neck is capped with a rubber septum, and the stirred solution is cooled in an ice bath for 5 min.A solution of 8-bromo-1-octanol (5.0 mL, 6.11 g, 29.2 mmol, 1.00 equiv) (Note 4) in CH 2 Cl 2 (10 mL) (Note 1) is added via syringe over 5 min.The reaction mixture is allowed to warm to rt, and the resulting heterogeneous solution (a white precipitate formed) is stirred for 4 h.The progress of the reaction is followed by TLC analysis on SiO 2 (10% EtOAc/hexanes as the eluent; visualization with a KMnO 4 stain; the alcohol starting material has an R f = 0.2, and the chloride product has an R f = 0.9) (Note 5).After the alcohol is consumed, the reaction is diluted with pentane (200 mL), and the mixture is filtered through a pad of SiO 2 (7 cm diameter × 6 cm height) in a sintered glass funnel.The SiO 2 is washed with additional pentane (400 mL).The filtrate is concentrated by rotary evaporation (20 mmHg, 30 °C), which furnishes the desired product as a colorless oil (6.23-6.44 g, 94-97 % yield) (Note 6).The product is used in the next step without further purification. B. Triethyl(pent-4-enyloxy)silane (2)An oven-dried, 200-mL, two-necked, round-bottomed flask equipped with an argon inlet and a magnetic stirbar (octagonal, molded pivot ring, 25 mm length and 6 mm diameter) is Safety and Waste Disposal Information All hazardous materials should be handled and disposed of in accordance with "Prudent Practices in the Laboratory"; National Academy Press; Washington, DC, 1995. 1 Dichloromethane (>99.5%) was purchased from Kanto Chemical Co., Inc. (water content <0.001%) and purified by Glass Contour solvent systems.The submitters purchased dichloromethane (>99.8%)from J.T. Baker (water content <0.02%), which was purified by passage through activated alumina under argon.2 Imidazole (99%) was purchased from Alfa Aesar and used as received.3 Dichlorotriphenylphosphorane (95%) was purchased from Aldrich and used as received.4 8-Bromo-1-octanol (95%) was purchased from Alfa Aesar and used as received.5 Analytical thin-layer chromatography was performed using Merck silica gel 60 F254 plates (0.25 mm).6 Compound 1 has the following properties: IR (film): 2931,