Reaktionen von 4,4-Bis(trifluormethyl)-1,3-diazabuta-1,3-dienen. Synthese trifluormethyl-substituierter Heterocyclenvia Baylis-Hillman-Reaktion

Summary 4,4-Bis(trifluoromethyl)-1,3-diazabuta-1,3-dienes and ,-unsaturated heteromultiple bond systems react to givebis(trifluoromethyl) substituted heterocycles. The first step of the formal [4+2] cycloaddition represents aBaylis-Hillman reaction.

Prof. Dr. Rolf Huisgen zum 75. Geburtstag gewidmet     

Heterocyclen-synthesen mit 4,4-bis(trifluormethyl)-1,3-diazabuta-1,3-dienen, II [1] spektroskopische untersuchung der isonitril- und dimethoxy-carben-addukte

[4+1] Cycloaddition reactions of 4,4-bis(trifluoromethyl)-1,3-diazabuta-1,3-dienes 3, accessible by reaction of amidines with hexafluoroacetone in the presence of dehydrating reagents, with isonitriles and dimethoxycarbene are described. Configuration of the isonitrile adducts 5 – 9 can be determined on basis of the ¹⁹F NMR data.     

CC-kupplungen von CO2 mit 1,3-dienen an eisen(0)-komplexen; carboxylatbildung und folgereaktionen

1,3-Dienes react with CO₂ at ligand-iron(0) systems to form η³-allyl carboxylates. The dynamic allylic system is influenced by addition of further ligands such as phosphanes or maleic acid anhydride or acetic acid anhydride. The direction of this influence is shown on the basis of the products generated by protonolysis or insertion of CO₂. When substituted 1,3-dienes are used, the 1/1 coupling step is regioselective. For example, with 1,3-pentadiene and CO₂ only two η³-allyliron carboxylates in the molar ratio 1/1 are formed. This isomer ratio confirms that the coupling reaction is kinetically controlled.     

Synthese und reaktionen von 1-germcyclohexa-2,4-dienen und 1-germacyclohexa-2,4-dien-eisentricarbonylen

1,1-Diakyl(aryl)4-alkyl(aryl)-4-methoxy-1-germacyclohexa-2,5-dienes undergo ether cleavage with sodium in n-pentane or liquid ammonia. Hydrolysis of the resulting sodium salts yields the 1,1-dialkyl(aryl)-4-alkyl(aryl)-1-germacyclohexa-2,4-dienes. Reduction of 1-chloro-4-methoxy-1-germacyclohexa-2,5-dienes with LiAlH₄ can be directed to give the 1H-1-germacyclohexa-2,4-dienes with ether cleavage.The 1H-1-germacyclohexadienes are chlorinated by PCl₅ and brominated by N-bromosuccinimide to the 1-chloro- or 1-bromo-1-germacyclohexa-2,4-dienes, respectively. 1,1-Diethyl-4-phenyl-4-methoxy-1-germacyclohexa-2,5-diene reacts with PCl₃ with ether cleavage and formation of the 6-chloro-1-germacyclohexa-2,4-diene. Ether cleavage is also possible with BCl₃, the 1-phenyl-1-chloro-4R-4-methoxy-1-germacyclohexa-2,5-dienes are transformed into the 1-phenyl-1,6-dichloro-4R-1-germacyclohexa-2,4-dienes.The Fe(CO)₃ complexes of 1,1-dialkyl(aryl)-1-germacyclohexa-2,4-dienes were synthesized.     

Diencarbonsäuren aus 1,3-dienen und CO2 durch C-C-verknüpfung an nickel(0)

(Lig)Ni⁰ systems react with 1,3-dienes in the presence of CO₂ to give nickela carboxylates. The influence of ligands and temperature on the regioselectivity of the CC bond formation is elucidated. In some cases the nickela carboxylates undergo reductive elimination under the influence of maleic anhydride, and the coupled diene/CO₂ moiety rearranges to give the diene carboxylic acid. A possible reaction sequence is discussed.     

Molybdenum 1,4-diazabuta-1,3-diene tricarbonyl solvento complexes revisited: from solvatochromism to attractive ligand-ligand interaction

Various complexes of the types [Mo(DAD)(CO)(3)L] (L = CO, MeCN, MeOH, THF, DMSO, DMF, Me(2)CO, EtOAc, THT, Im(H), Im(1), tBuNC, nBu(3)P), (ER(4))[Mo(DAD)(CO)(3)X] (ER(4) = NEt(4)(+); X(-) = Cl(-), Br(-), I(-), NCS(-), CN(-) and ER(4)(+) = PPh(4)(+); X(-) = N(3)(-)), and (ER(4))[{Mo(DAD)(CO)(3)}(2)(μ-X)] (ER(4)(+) = NEt(4)(+); X(-) = CN(-), OAc(-) and ER(4)(+) = PPh(4)(+); X(-) = N(3)(-); DAD = N,N'-bis(2,6-dimethylphenyl)butane-2,3-diimine) were prepared by ligand exchange from cycloheptatriene molybdenum tricarbonyl. A total of 19 crystal structures were determined, including unprecedented structural characterization of molybdenum(0) coordination by dimethyl sulfoxide (DMSO), methanol, ethyl acetate (EtOAc), acetone, and N,N-dimethylformamide (DMF). Correlation of (13)C NMR shifts with the complex geometry suggests a direct ligand-ligand interaction between DAD and O-bonded coligands with C═O and S═O double bonds, such as EtOAc, Me(2)CO, DMF, and DMSO. Unexpectedly, the solvatochromic properties of these tricarbonyl complexes [Mo(DAD)(CO)(3)L] are unfavorable for the determination of Kamlet-Taft parameters of the corresponding solvent L. Contrastingly, the UV/vis absorption of [Mo(DAD)(CO)(4)] is strongly correlated with the Kamlet-Taft parameter π*, which is shown for 22 solvents, including seven room temperature ionic liquids.     

«Template»-Reaktionen I. Herstellung von tricyclischen und tetracyclischen Metallkomplexen aus aromatischen 1,2-Diaminen und 1,3-Dicarbonylverbindungen

The condensation of 1,2-phenylenediamine 1 and 1,3-dicarbonyl compounds 2 in the presence of a divalent metal ion such as Ni²⁺, Cu²⁺, Co²⁺, yields the tricyclic 4 or tetracyclic complexes 5 . The yields of these one step template reactions is very high in a large number of examples with differently substituted diamines 1 and 1,3-dicarbonyls 2 .     

4,5-Dihydro-1H-azepine aus aktivierten Cyclobutenen und 1,3-Dipolen

Cycloaddition of diphenylnitrile ylide to dicyanocyclobutene and of a mesoionic oxazolium-5-olate to isopropylidenecyclobutenone yields dihydroazepine derivatives by cleavage of the strained internal σ-bonds in the primarily formed bicyclic adducts.     

Die Trennung von 1,3-Butadien und 1-Buten

Ohne Zusammenfassung