Pyrrolderivate durch reaktion anionisierter schiffbasen mit α-halogenketonen

Wittig, Georg; Röderer, Rolf; Fischer, Sven

doi:10.1016/s0040-4039(01)86959-8

Cited by 20 publications

(8 citation statements)

References 5 publications

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“…69,70 The use of lithiated propylidenecyclohexylamine 137 illustrates both mechanisms by the formation of a mixture of both types of 1,2,4-and 1,3,4-trisubstituted pyrroles 138 and 139.…”

Section: Synthesis Of Pyrrolesmentioning

confidence: 99%

1-Azaallylic Anions in Heterocyclic Chemistry

2004

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“…69,70 The use of lithiated propylidenecyclohexylamine 137 illustrates both mechanisms by the formation of a mixture of both types of 1,2,4-and 1,3,4-trisubstituted pyrroles 138 and 139.…”

Section: Synthesis Of Pyrrolesmentioning

confidence: 99%

1-Azaallylic Anions in Heterocyclic Chemistry

2004

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“…The lithium 1-azaallyls 1a were excellent ligand transfer reagents, producing various metal-1-azaallyl complexes with intriguing coordination chemistry . The majority of attention paid to the chemistry of 1-aza-allylmetal complexes has been their use as reagents in carbon−carbon bond formation, as in controlled aldol condensation reactions or regioselective α-functionalization of ketones. , N -Silyl-1-azaallyl anions (formed via insertion of a nitrile into a lithium alkyl bond) have proved to be excellent synthons for the formation of heterocycles, as have 3-halo-1-azaallyllithium compounds …”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structures, Characterization, Dynamic Behavior, and Reactions of Novel Late Transition Metal(II) 1-Azaallyls

et al. 2004

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A series of homoleptic late transition metal(II) 1-azaallyl compounds ([M(L)2] {L = η3-N(SiMe3)C(tBu)CH(C6H4Me-4), M = Fe (5), Co (6), or Ni (7)}, [M(L1)2] {L1 = η3-N(SiMe3)C(Ph)CH(SiMe3), M = Ni (8) or Pd (9)}, [M(L2)2] {L2 = η3-N(SiMe3)C(tBu)CH(SiMe3), M = Fe (10) or Co (11)}, or [M(L3)2] {L3 = η1-N(SiMe3)C(tBu)CH(C10H7-1), M = Fe (12)} have been prepared by reactions of anhydrous late transition metal halides {MX2 = FeBr2, CoCl2, [NiBr2(dme)], or [PdCl2(cod)]} with the appropriate lithium or potassium 1-azallyl KL (1), [LiL1(thf)]2 (2), [LiL2]2 (3), or KL3 (4) in a 1:2 molar ratio. The heteroleptic 1-azallylnickel(II) complex Ni(η3-C3H5)(L3) (13) was prepared from [{Ni(η3-C3H5)(μ-Br)}2] with a stoichiometric amount of the 1-azaallylpotassium reagent KL3 (4). Single-crystal X-ray analysis revealed the 1-azaallyl to be bonded to the metal center in an η3-NCC mode in the mononuclear compounds 5−8 and 10, whereas in 12 the 1-azallyl is N-bound in the κ1-enamido fashion. The iron(II) (5, 10, and 12) and cobalt(II) (6 and 11) compounds are paramagnetic and have magnetic moments in the range 5.01−5.61 μB and 2.73−3.01 μB, respectively, characteristic of a high-spin d6 and low-spin d7 electronic configuration, respectively. The diamagnetic group 10 metal 1-azaallyl compounds (7−9 and 13) were fully characterized by multinuclear NMR spectroscopy and were found to be a mixture of isomers. Several NOE, two-dimensional, and saturation transfer NMR spectroscopic experiments were used to elucidate the nature of the three isomers. Variable-temperature and variable-temperature saturation transfer NMR spectroscopic experiments showed the isomers of each of compounds 7−9 to be involved in a dynamic process. Electrochemical and oxidation studies on compounds 5 and 6 are reported, as are α-olefin oligomerization reactions catalyzed by 13 with MAO or B(C6F5)3.

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“…A set of structurally related substrates has also been converted into pyrroles bearing multiple substituents by initial silver-catalyzed isomerization of the propargyl moiety to an allene, followed by condensation of the resulting intermediates with primary amines, and final goldcatalyzed 5-exo-dig cyclizations [96]. It has been known for some time that pyrroles may be obtained from the reactions of azaallylic anions with suitable a-haloketones [97]. A new application of azaallylic anions in pyrrole synthesis has been realized by conversion of the a-haloimines 40 into the intermediates 41, which in turn are cyclized to the 1-pyrrolines 42, eventually giving the pyrroles 43 (Scheme 4.14), including the 3-chloro derivative (R 2 ¼Ph, R 3 ¼Cl) [98].…”

Section: 42mentioning

confidence: 99%