GENERATION AND REACTIVITY OF SUBSTITUTION-LABILE DICHLOROMETHANE AND CHLOROBENZENE ADDUCTS OF THE CHIRAL PENTAMETHYLCYCLOPENTADIENYL RHENIUM LEWIS-ACID [(ETA-5-C5ME5)RE(NO)(PPH3)]+

Reactions of (eta5-C5Me5)Re(NO)(PPh3)(CH3) (5) and HBF4.OEt2 in CH2Cl2 (-80-degrees-C) or C6H5Cl (-45-degrees-C) give the chlorohydrocarbon complexes [(eta5-C5Me5)Re(NO)(PPh3)(ClCH2Cl)]+BF4- (3) and [(eta5-C5Me 5)Re(NO)-(PPh3)(ClC6H5)]+BF4-(4). The latter is a mixture of linkage a nd constitutional isomers. Reactions of 3 and halide ions X- give main ly (eta5-C5Me5)Re(NO)(PPh3)(CI) (6) and XCH2Cl, but 4 and Ph3PCH3+I- y ield (eta5-C5Me5)-Re(NO)(PPh3)(I) (84%). Reaction of 3 and Et4N+CN- gi ves comparable amounts of 6 and (eta5-C5Me5)Re(NO)-(PPh3)(CN). The lat ter forms in 90% ee when (-)-(R)-5 (>95% ee) is employed. When 3 is wa rmed to -35-degrees-C, the oxidative addition product eta5-C5Me5)Re(NO )(PPh3)(Cl)(CH2Cl)]+BF4-(10)forms. Reaction of 3 and CH3I gives [(eta5 -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 g ive the alkene complexes [(eta5-C5Me5)Re(NO)(PPh3)(H2C=CHR)]+BF4-as mi xtures of RS,SR/RR,SS diastereomers. Equilibration (50-100-degrees-C) gives only the RS,SR diastereomers, indicating high enantioface bindin g selectivities. Similar substitutions involving ethyne and nonracemic 4 are described.