Azepines metal complexes

Schmidt reaction of ketones, 7, 530 from thienylnitrenes, 4, 820 tautomers, 7, 492 thermal reactions, 7, 503 transition metal complexes reactivity, 7, 28 tungsten complexes, 7, 523 UV spectra, 7, 501 X-ray analysis, 7, 494 1 H-Azepines conformation, 7, 492 cycloaddition reactions, 7, 520, 522 dimerization, 7, 508 H NMR, 7, 495 isomerization, 7, 519 metal complexes, 7, 512 photoaddition reactions with oxygen, 7, 523 protonation, 7, 509 ring contractions, 7, 506 sigmatropic rearrangements, 7, 506 stability, 7, 492 N-substituted mass spectra, 7, 501 rearrangements, 7, 504 synthesis, 7, 536-537... 

NMR, 3, 542 oxidation, 3, 546 phosphorescence, 3, 543 photoelectron spectra, 3, 542 photolysis, 3, 549 reactions, 3, 543-555 with alkenes, 3, 50 with alkynes, 3, 50 with IH-azepines, 3, 552 with azirines, 3, 554 with cyclobutadiene, 3, 551 with cyclopropenes, 3, 550 with dimethylbicyclopropenyl, 3, 551 with heterocyclic transition metal complexes, 7, 28 29... 

The use of metal complexed heterocyclic polyenes in these cycloadditions has also proven useful, as both the 1,1-dioxythiepine and azepine derivatives 250 and 253 took part in [6 + 4]- and [6+ 2]-photocycloadditions, respectively, to afford good yields of the... 

Anomalous behavior is exhibited by the tricarbonylruthenium complex of 1-methoxycar-bonyl-1//-azepine in that at room temperature with TCNE, perfluoropropanone or l,l-dicyano-2,2-bis(trifluoromethyl)ethylene, exo-2,5-adducts, e.g. (143), are obtained. Deuteration studies reveal that the addition is non-concerted and involves an initial electrophilic attack by the 2u--system at the uncoordinated double bond of the azepine-metal carbonyl complex <77JCS(D)204). 

Application of the reaction to the 2-azidobenzoyl derivative of diethylene glycol monomethyl ether 92, in a mixture of tetrahydrofuran and diethylene glycol monomethyl ether as the nucleophile, affords 2-(2-methoxyethoxy)ethyl 2-[2-(2-methoxyethoxy)ethoxy]-37/-azepine-3-carbo-xylate (93), which displays metal cation complexing properties towards lithium, potassium, and. to a lesser extent, barium and calcium cations.198... 

The chemistry of unsaturated azepines is dominated by their polyene character. The absence of ir-delocalization confers instability on the ring system as witnessed by the many and various ring transformations undergone in acid and base solution, and under thermal and photolytic conditions. Most of the major reactions of azepines involve the neutral molecule e.g. cycloadditions (Section 5.16.3.8.1), metal carbonyl complexation (Section 5.16.3.8.2), dimerizations (Section 5.16.3.2.3) and photo- and thermo-induced valence isomerizations (Section 5.16.3.2.1). 

The facility of 1H-azepines to form transition metal carbonyl complexes was realized soon after they were first synthesized. Variable temperature HNMR studies on the tricarbonyliron complex formed either by photolysis of 1-ethoxycarbonyl-l//-azepine with tricarbonyliron in THF, or by heating the azepine with nonacarbonyldiiron in hexane, demonstrated that it undergoes rapid reversible valence tautomerism and that there is considerable restricted rotation about the N—CO bond (B-69MI51600). The molecular geometry of the complex has been determined by X-ray analysis (see Section 5.16.2.2). 

Carbonylation of 2,3-homo-l//-azepines has been effected by means of their metal and carbonyl complexes and provides a useful route to a variety of isomeric azabicyclo-nonadienones. For example, the tricarbonyliron complex with carbon monoxide at 80 °C and 160 atm yields the 9-oxo-2-azabicyclo[3.3.l]nona-3,7-diene (167) (57%) or the 9-oxo-2-azabicyclo[3.2.2]nona-3,6-diene (168) (60%) depending on the exo or endo configuration of the tricarbonyliron complex. A third isomer, namely ethyl 7-oxo-9-azabicyclo[4.2.1]nona-2,4-diene-9-carboxylate (169), is formed on heating (125 °C) the azepine with carbon monoxide under pressure in the presence of the rhodium carbonyl complex [Rh(CO)Cl2] (78CB3927). 

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