Various β-, γ-, and δ-alkynols have been reacted with the 16e- fragment [(triphos)Re(CO)2]+ generated in situ by H2 elimination from [(triphos)Re(CO)2(η2-H2)]BF4 [triphos = MeC(CH2PPh2)3]. Irrespective of the length of the alkyl chain between the C≡C and OH functional groups in the ω-alkynol, 2-oxacyclocarbene complexes are obtained. These include the 2-oxacyclopentylidene derivatives [(triphos)-Re(CO)2{=CCH2CH2CH 2O}]BF4 and [(triphos)Re(CO)2-{=CCH2CH2CH(Me)O}]BF 4, the 2-oxacyclohexylidene dervivatives [(triphos)Re(CO)2{=CCH2CH2CH2CH 2O}]BF4 and [(triphos)Re(CO)2{=CCH2CH2CH 2CH(Me)O}]BF4, and the 2-oxacycloheptylidene complex [(triphos)Re(CO)2{=CCH2CH2-CH 2CH2CH2O}]BF4. The latter compound contains a unprecedented seven-membered oxacarbene ring. The rheniumassisted δ-alkynol to 2-oxacyloheptylidene rearrangement proceeds via the hydroxybutylvinylidene kinetic intermediate [(triphos)Re(CO)2{C=C(H)CH2CH2CH 2CH2OH}]BF4, which has been characterized in both the solid state and solution. An X-ray analysis has been carried out on a single crystal of [(triphos)Re(CO)2{=CCH2CH2CH(Me)O}]BF 4. The structure of this complex consists of [(triphos)Re(CO)2{= CCH2CH2CH(Me)O}]+ cations and tetrafluoroborate anions with no interspersed solvent molecules. A facial triphos ligand, two cis-disposed carbonyl groups and a 2-oxacyclopentylidene ligand coordinate the Re centre in a slightly distorted octahedral environment.
2-oxacyclopentylidene, 2-oxacyclohexylidene, and 2-oxacycloheptylidene rhenium complexes by reaction of omega-alkynols with the [{MeC(CH2PPh2)(3)}Re(CO)(2)](+) auxiliary
MARCHI, Andrea;MANTOVANI, Nicoletta;MARVELLI, Lorenza;ROSSI, Roberto
1998
Abstract
Various β-, γ-, and δ-alkynols have been reacted with the 16e- fragment [(triphos)Re(CO)2]+ generated in situ by H2 elimination from [(triphos)Re(CO)2(η2-H2)]BF4 [triphos = MeC(CH2PPh2)3]. Irrespective of the length of the alkyl chain between the C≡C and OH functional groups in the ω-alkynol, 2-oxacyclocarbene complexes are obtained. These include the 2-oxacyclopentylidene derivatives [(triphos)-Re(CO)2{=CCH2CH2CH 2O}]BF4 and [(triphos)Re(CO)2-{=CCH2CH2CH(Me)O}]BF 4, the 2-oxacyclohexylidene dervivatives [(triphos)Re(CO)2{=CCH2CH2CH2CH 2O}]BF4 and [(triphos)Re(CO)2{=CCH2CH2CH 2CH(Me)O}]BF4, and the 2-oxacycloheptylidene complex [(triphos)Re(CO)2{=CCH2CH2-CH 2CH2CH2O}]BF4. The latter compound contains a unprecedented seven-membered oxacarbene ring. The rheniumassisted δ-alkynol to 2-oxacyloheptylidene rearrangement proceeds via the hydroxybutylvinylidene kinetic intermediate [(triphos)Re(CO)2{C=C(H)CH2CH2CH 2CH2OH}]BF4, which has been characterized in both the solid state and solution. An X-ray analysis has been carried out on a single crystal of [(triphos)Re(CO)2{=CCH2CH2CH(Me)O}]BF 4. The structure of this complex consists of [(triphos)Re(CO)2{= CCH2CH2CH(Me)O}]+ cations and tetrafluoroborate anions with no interspersed solvent molecules. A facial triphos ligand, two cis-disposed carbonyl groups and a 2-oxacyclopentylidene ligand coordinate the Re centre in a slightly distorted octahedral environment.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
