27072-19-1

Upstream product

• 930-68-7 cyclohexenone 
• 80436-01-7 [Co(diphenylglyoxime^(1-))2(pyridine)] 

Relevant academic research and scientific papers

Transition-metal mediated exo selective and enantioselective Diels-Alder reactions for the preparation of octalones with unusual stereochemistries. Reactions of 2-cobaloxime substituted 1,3-dienes with cyclohexenone in optically active Lewis acid catalyzed [4 + 2] cycloadditions

2-Cobaloxime-E-1,3-pentadienyl complexes (cobaloxime = pyridine(dimethyl or diphenylglyoxime)2Cobalt (III)) react with cyclohexenone in enantioselective Lewis acid catalyzed [4 + 2] cycloaddition reactions. These cycloaddition reactions produce octalones with cis ring junctions through exo transition states. The octalones are removed from the cobalt via demetallation reactions which replace the cobalt with a hydrogen and provide pyr(dmg)2CoMe which can be recycled into the synthesis of the starting dienyl complex. The enantiomeric purity of the demetallated octalones was determined by gas chromatographic analysis.

A study of cis influence in alkyl cobaloximes

Thirty-nine alkylcobaloximes have been synthesized (many of them new) and characterized with three different dioxime ligands, dmgH, dpgH and chgH. The chgH cobaloximes have been synthesized for the first time from ClCo(chgH)2Py complexes. A rapid purification procedure using column chromatography affording analytically pure products has been established for all the three series of cobaloximes. Methanol has been found to be the best solvent for the study of cobalt-carbon charge transfer (Co-C CT) band as the alkylcobaloximes exhibit a prominent maxima in this solvent. For MeCo(dpgH)2Py the Co-C CT band is not resolved; a λmax value of 453. 6 nm is proposed for it. The literature value of 473 nm is doubtful. The variation of λmax values with increasing alkyl chain length is surprisingly similar for all the three series of cobaloximes. 13C-Spectroscopy has revealed that the Pα experiences the most cis influence and Pβ the least. The cis influencing ability of the chgH ligands have been found to be negligible (as compared to dpgH) on the alkyl chain as well as on the Pβ and Pγ carbons. 1H-NMR studies indicate that the cis influence is felt most by the cobalt bound methylene protons followed by Pα and Pβ. Interestingly, the O-H-O resonance for the chgH cobaloximes appear ～ 0.5 ppm upfield than the analogous dmgH complexes in all the thirteen alkylcobaloximes. The order of cis influencing ability has been found to be dpgH > chgH > dmgH by all the three spectroscopic techniques. This sequence is exactly the reverse order of the corresponding Co(I) nucleophilicities. C=N and N-O stretching frequencies in the IR studies for three series of cobaloximes follow the order dmgH > chgH > dpgH. The order can be explained if one invokes the electronic effect of the substituents on the dioximic moiety.

Influence of the redox state of the ligand on the dealkylation of substituted methylcobaloximes in the presence of heavy metal ions

The synthesis of cobaloxime and methylcobaloxime containing sterically hindered 2,6-di-tert-butylphenol fragments in the ligand is described. Spectral studies of the demethylation of methylbis(dimethylglyoximato)cobalt (1a), methylbis(diphenylglyoximato)c