ISSN:
0009-2940
Keywords:
Aminocarbene complexes, of chromium and tungsten
;
3-Aza-1-metalla-1,3-dienes, of chromium and tungsten
;
5-Aza-1-metalla-1,3,5-trienes, cyclization to 2H-pyrroles
;
2H-Pyrrole complexes, of chromium and tungsten
;
Pyrroles, syntheses by metal-induced [3 + 2] cycloaddition reactions
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organic Syntheses via Transition Metal Complexes, 551). - 5-Aza-1-metalla-1,3,5-trienes of Chromium and Tungsten, and Their Cyclization to 2H-Pyrrole Complexes5-Aza-1-metalla-1,3,5-trienes 5 and 6 [LnM = C - C = C - N = C, a: LnM = Cr(CO)5, b: W(CO)5] are obtained in two steps from aminocarbene complexes 1 [LnM = C(NH2)Ph, a: LnM = Cr(CO)5, b: W(CO)5]. The first step involves the condensation of 1 with benzaldehyde (2) in the prescence of TiCl4/Et3N to give 3-aza-1-metalla-1,3-dienes 3 (LnM = C - N = C). 3 adds to the 1-aminoalkyne 4 to give 5 and 6 by a chain extension of two carbon atoms. The trans isomers 5 are formed as the major products and are stable both in the solid state and in solution. The cis isomers 6 undergo a novel-type cyclization to give 2H-pyrrole complexes 8. Triene 5b was characterized by an X-ray analysis.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911241131
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