ISSN:
0009-2940
Keywords:
Homopyrroles, mono- and bicyclic
;
[3 + 2] Cycloadditions of N-vinylaminocarbene iron complexes to alkynes
;
5-Aza-1-ferra-1,3,6-trienes
;
Intramolecular cyclopropanation, metal-induced
;
2H-Pyrrolium tricarbonyl iron complexes
;
Pyridine, 1,2-dihydro-, tricarbonyl iron complexes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organic Syntheses via Transition Metal Complexes, 561). - Homopyrroles and Dihydropyridines from N-Vinylamino-carbene Iron Complexes and Alkynes by Cyclisation of Intermediate 5-Aza-1-metalla-1,3,6-trienes2,3-Homopyrroles 5 and dihydropyridines 7, 8 are obtained by the light-induced addition of alkynes 4a - d (RC = CR1; R, R1 = H, CH3, C6H5, CO2CH3) to the N-vinylaminocarbene iron complex (= 3-aza-1-ferra-1,4-diene) 3. The formation of the N-heterocycles 5 and 7 as well as that of the pyrrolium carbonylferrates 6 can be explained by assuming the chelated 5-aza-1-ferra-1,3,6-trienes A to be key intermediates in this reaction. Stereochemical considerations lead to the conclusion that the ring expansion of the 4 1/2-membered ring of 3 to the 6 1/2-membered ring of A occurs without prior ≡ decomplexation by the insertion of a C = C unit into the M = C bond. NMR measurements and MNDO calculations suggest that the bicyclic homopyrroles 5 are in equilibrium with the novel monocyclic homopyrrole species 9. The structure of 6c has been established by X-ray diffraction analysis.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911241132
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