Generation and Reactivity of Substitution-Labile Dichloromethane and Chlorobenzene Adducts of the Chiral Pentamethylcyclopentadienyl Rhenium Lewis Acid [(.eta.5-C5Me5)Re(NO)(PPh3)]+ Academic Article uri icon

abstract

  • Reactions of (η5-C5Me5)Re(NO)(PPh3)(CH3) (5) and HBF4·OEt2 in CH2Cl2(-80 °C) or C6H5Cl (-45 °C) give the chlorohydrocarbon complexes [(η5-C5Me5)Re(NO)(PPh3)(ClCH2Cl)]+BF4-(3) and [(η5-C5Me5)Re(NO)(PPh3)(ClC6H5)]+BF4-(4). The latter is a mixture of linkage and constitutional isomers. Reactions of 3 and halide ions X-give mainly (η5-C5Me5)Re(NO)(PPh3)(Cl) (6) and XCH2Cl, but 4 and Ph3PCH3+I- yield (η5-C5Me5)Re(NO)(PPh3)(I) (84%). Reaction of 3 and Et4N+CN- gives comparable amounts of 6 and (η5-C5Me5)Re(NO)(PPh3)(CN). The latter forms in 90% ee when (-)-(R)-5 (>95% ee) is employed. When 3 is warmed to -35 °C, the oxidative addition product [(η5-C5Me5)Re(NO)(PPh3)(Cl)(CH2Cl)]+BF4-(10) forms. Reaction of 3 and CH3I gives [(η5-C5Me5)Re(NO)(PPh3)(ICH3)]+BF4-, but 3 converts to 10 in the presence of excess styrene or ethyne. Reactions of 4 and 1-pentene or styrene give the alkene complexes [(η5-C5Me5)Re(NO)(PPh3)(H2C═CHR)]+BF4- as mixtures of RS,SR/RR,SS diastereomers. Equilibration (50-100 °C) gives only the RS,SR diastereomers, indicating high enantioface binding selectivities. Similar substitutions involving ethyne and nonracemic 4 are described. © 1994, American Chemical Society. All rights reserved.

author list (cited authors)

  • Peng, T., Winter, C. H., & Gladysz, J. A.

citation count

  • 37

publication date

  • June 1994