ISSN:
0947-6539
Keywords:
electrophilic additions
;
N-pyrrolyl complexes
;
rearrangements
;
rhenium compounds
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reaction of [{Re}(OTf)] (1; {Re} - (η5-C5H5)Re(NO)(PPh3) and potassium pyrrolide gives the N-pyrrolyl complex 2, 88%). Reactions of 2 with (CF3CO)2O/N(C2H5)3 and CH3O2CC=CCO2CH3 give 3- and 2-substituted pyrrolyl complexes respectively (3, R/R′ = H/COCF3, 77%; 5, R/R′ = C(CO2CH3)=CHCO2CH3/H, 69-87%). Free pyrrole is much less reactive towards these reagents. Reactions of 2 and TfOH or HBF4·OEt2 give the 2H-pyrrole adducts +X- (7+X-; 89-83%). At 0-25°C in CH2Cl2, these rearrange to the carbon-ligated tautomers +X-(8+X-) and then +X-; (9+X-; 72-96 h, 90-96%). Reaction of 1 and pyrrole in refluxing toluene gives 8+TfO- and then 9-TfO- (92%). However, 1 and pyrrole react too slowly in CH2Cl2 to be intermediates in the conversion of 7+TfO- to 9+TfO-. Reaction of 9+ TfO- and KH gives the C-pyrrolyl complex (68%), which adds TfOH to give 9+TfO-. Mechanistic aspects of the preceding reactions are discussed. The crystal structures of 2 and 9+TfO- are determined, and the NC4Hx ligand conformations analyzed with extended Hückel MO calculations.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19950010506
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