Chiral diazadiene and β-ketoimine ligands from the reaction of N,N′-bis-aryl-oxalimidoylchlorides with (S)-prolinol and their reactivity towards iron carbonyls

Imhof, Wolfgang; Göbel, Angela; Beckert, Rainer; Billert, Thomas; Görls, Helmar

doi:10.1016/s0022-328x(99)00439-8

Cited by 10 publications

(7 citation statements)

References 56 publications

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“…The pattern of IR bands in the region typical for terminal carbon monoxide ligands is identical to related [Fe 2 (CO) 6 (1,4-diazabutadiene)] complexes [2]. All mass spectra show peaks corresponding to the molar masses of the complete molecules and fragmentations corresponding to the loss of CO ligands, the iron atoms and subsequent degradation of the ligands.…”

Section: Resultsmentioning

confidence: 55%

“…In analogy to the related proline based diazadiene substrates oxadiazines 1a-e produce chiral spiro-lactams 3a-e as a result of a formal [2+2+1] cycloaddition reaction of one of the exocyclic imine functions with carbon monoxide and ethylene in the presence of catalytic amounts of Ru 3 (CO) 12 [2]. Yields of 3a-e decrease in the same order as it has been observed for the formation of the dinuclear iron carbonyl complexes 2a-e leading to only trace amounts of 3d and 3e whereas 3a-c could be purified and fully characterized.…”

Section: Resultsmentioning

confidence: 99%

“…During the last decades a number of cycloaddition reactions catalyzed by transition metals have been reported and the progress of this field of research has been thoroughly reviewed [1]. We have been able to show that chiral diazadienes from the reaction of enantiomerically pure S-prolinol with N,N 0 -bis-aryl-oxalimidoylchlorides may be reacted either with Fe 2 (CO) 9 under thermal or with Fe(CO) 5 under photochemical activation to give unsymmetrically coordinated dinuclear iron carbonyl complexes [2]. In addition, the synthesis of chiral spiro-lactams in a formal [2+2+1] cycloaddition reaction from the diazadiene derivatives, carbon monoxide and terminal alkenes was achieved regioselectively at the imine function next to the oxazine oxygen atom [3].…”

Section: Introductionmentioning

confidence: 99%

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Novel diazadienes based on 1,3,4-oxadiazines: Ligands in iron carbonyl complexes and substrates in catalytic [2+2+1] cycloaddition reactions

Kaleta

Fleischhauer

Görls

et al. 2009

Journal of Organometallic Chemistry

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Section: Resultsmentioning

confidence: 55%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel diazadienes based on 1,3,4-oxadiazines: Ligands in iron carbonyl complexes and substrates in catalytic [2+2+1] cycloaddition reactions

Kaleta

Fleischhauer

Görls

et al. 2009

Journal of Organometallic Chemistry

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“…In these complexes the Fe 2 (CO) 6 moiety binds in an unsymmetrical manner; one of the iron atoms co-ordinates to both imine nitrogen atoms, whereas the second is connected to one of the C^N double bonds in a side-on fashion. 5 Synthetic receptors selective for the enantiomers of Troger's base have been prepared by the molecular imprinting of compound 5 in methacrylic acid^ethylene glycol dimethacrylate copolymers. Spectroscopic evaluation of the self-assembly phase, prior to polymerisation, demonstrated the formation of template-functional monomer adducts of K diss 0.7AE0.1 mM at 293 K in chloroform.…”

Section: Nitrogenmentioning

confidence: 99%

6 Nitrogen, phosphorus, arsenic, antimony and bismuth

Kee

2000

Annu. Rep. Prog. Chem., Sect. A

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“…Bis-amidines of type 2 are versatile building blocks for several heterocycles [1][2][3] as well as being ligands for catalytical active metals. [4][5][6] Their syntheses are easily feasible by aminolysis reactions of bis-imidoylchlorides 1 with various amines. In contrast to this, there exist only a few bisamidines of type 3 which possess two primary NH 2 groups.…”

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Bis-Amidines as Useful Building Blocks for Heterofulvenes and -Fulvalenes

2001

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An easily feasible synthesis for bis-amidines of type 3 was developed via an aminolysis reaction of imidoyl chlorides 1 with gaseous ammonia. Depending on the nature of the electrophilic cyclization reagent, these amidines show a different reactivity. On treatment with orthoesters, the fused imidazoles 5 were obtained which involved the participation of two different kinds of nitrogen atoms in the cyclization. In contrast to this, carboxylic acid chlorides are able to react selectively at the NH 2 -groups under formation of the fulvenoid 4H-imidazoles 6. The same regioselectivity was observed for chlorodimethylimmonium chloride thus leading, via the dimerization of cyclic orthoamides, to the 1,4,5,8-tetraazafulvalenes 8.Bis-amidines of type 2 are versatile building blocks for several heterocycles 1-3 as well as being ligands for catalytical active metals. 4-6 Their syntheses are easily feasible by aminolysis reactions of bis-imidoylchlorides 1 with various amines. In contrast to this, there exist only a few bisamidines of type 3 which possess two primary NH 2 groups. A limiting factor for this might be the inconvenient handling of dicyane as the starting material. Thus, only a small number of amidines 3 have been reported as being synthesized by amine additions to dicyane 7-9 or by aminolysis reactions of derivatives of dicyane as imino esters 10-15 or diiminosuccinonitrile. 16 However, another route to 3 starting from bis-imidoylchlorides 1 proceeds via an aminolysis reaction with ammonia. 17 According to an existing protocol 17 in the course of which ethanol has been employed as the solvent only a small amount of amidine 3a was obtained, in addition to phenyl isonitrile and tarry material. Obviously, imidoylchlorides of type 1 behave similarly to oxalyl chloride, which in the presence of nucleophiles often undergoes a C-C cleavage reaction.We report here on the aminolysis of bis-electrophiles 1 with gaseous ammonia to give the desired amidines 3 in high yields. On treatment of a suspension of bis-imidoylchlorides 1 in dry THF with a stream of dried gaseous ammonia, the products 3a-g were formed in a smooth reaction (Scheme 1). The progress of this aminolysis can be followed by fading of the intensive yellow color of the reaction mixture and was effectively monitored by TLC. Simple recrystallization gives the amidines 3a-g as white to yellowish crystals in high purity. The application of elevated pressure (5 bar, glas autoclave) lead to higher yields and a shortening of the reaction times (1 hour, starting from 0.1 mol of 1). The X-ray structural determination of 3b revealed a transoid arrangement of both aryl groups (Figure 1). The C=N fragments are located at the aromatic residues whereas the bond length for C-NH 2 corresponds to a typical C-N single bond. Contrary to the solid state structures, in solution, 3 undergoes facile E/Z-interconversion and prototropic processes called "tautomeric rotations". 18 NMR experiments performed at -60°C for the trifluoromethyl substituted derivative 3g revealed the coexiste...

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Chiral diazadiene and β-ketoimine ligands from the reaction of N,N′-bis-aryl-oxalimidoylchlorides with (S)-prolinol and their reactivity towards iron carbonyls

Cited by 10 publications

References 56 publications

Novel diazadienes based on 1,3,4-oxadiazines: Ligands in iron carbonyl complexes and substrates in catalytic [2+2+1] cycloaddition reactions

Novel diazadienes based on 1,3,4-oxadiazines: Ligands in iron carbonyl complexes and substrates in catalytic [2+2+1] cycloaddition reactions

6 Nitrogen, phosphorus, arsenic, antimony and bismuth

Bis-Amidines as Useful Building Blocks for Heterofulvenes and -Fulvalenes

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