New chiral cyclopalladated complexes based on the pinane and bornane imines

Кучин, А. В.; Gur’eva, Ya. A.; Фролова, Л. Л.; Alekseev, I. N.; Zalevskaya, O. A.

doi:10.1007/s11172-013-0101-6

Cited by 11 publications

(8 citation statements)

References 5 publications

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“…Oily yellow liquid, 54% yield, [D] D 21 +32.3° (c 0.2, CHCl 3 ). The spectral data corresponded to the opposite enantiomer of the reported one [8].…”

Section: Methodsmentioning

confidence: 77%

“…The imines and Pd complexes were synthesized according to known methods [8,10]. (1S,2S,5S)-3-(Diphenylmethylimino)2,6,6-trimethylbicyclo[3.1.1]heptan-2-ol (2).…”

Section: Methodsmentioning

confidence: 99%

“…We reported previously the synthesis of the (1R,2R,5R)-enantiomer of 2D-hydroxypinan-3-one diphenylmethylimine [8].…”

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confidence: 99%

“…The syntheses of these complexes were described in our previous works [8,10]. Bornane palladacycle 5 turned out to be more stable.…”

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confidence: 99%

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New Optically Active CN-Palladacycles Based on 2α-Hydroxypinan-3-One and Camphor Derivatives

et al. 2014

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The ligand (-)-2D-hydroxypinan-3-one diphenylmethylimine was synthesized and studied. New dinuclear CN-palladacycles and their mononuclear triphenylphosphine derivatives were obtained. It was shown that ortho-palladation of terpene diphenylmethylimines produced pure stereoisomers.Natural monoterpenoids that are isolated from renewable plant sources are convenient chiral starting materials for synthesizing important classes of compounds, in particular, for preparing chiral cyclopalladated complexes, which are being applied more and more widely in asymmetric synthesis [1,2]. They were used successfully as catalysts for cross-coupling reactions [3,4], alkene hydroarylation [5], and allyl alkylation [6].We selected the bicyclic monoterpenoids D-pinene and camphor as the starting materials for synthesizing homochiral ligands. This was due to their commercial availability and facile chemical modification. It was especially noteworthy that ligands could possibly be obtained as pure enantiomers.Oxidation of (+)-D-pinene produced (-)-2D-hydroxypinan-3-one (1) [7], condensation of which with diphenylmethylamine synthesized the (1S,2S,5S)-diphenylmethylimine (2) in 54% yield (Scheme 1). We reported previously the synthesis of the (1R,2R,5R)-enantiomer of 2D-hydroxypinan-3-one diphenylmethylimine [8].Cyclopalladation of 2D-hydroxypinan-3-one and camphor benzylimines was studied before [8-10]. The 2D-hydroxypinan-3-one derivatives, in contrast with bornane ligands, were rather easily cyclopalladated upon reaction with Li 2 PdCl 4 . The new dinuclear palladacycle 3 was synthesized in 58% yield under these conditions (Scheme 1).The structure of 3 was confirmed by NMR spectroscopy. The ortho-disubstituted aromatic ring was identified by characteristic NMR resonances in the region of aromatic protons that included four non-equivalent proton resonances with a characteristic splitting. The multiplicity and integrated intensity of proton resonances for the second mono-substituted benzene ring persisted in the PMR spectra.

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“…Oily yellow liquid, 54% yield, [D] D 21 +32.3° (c 0.2, CHCl 3 ). The spectral data corresponded to the opposite enantiomer of the reported one [8].…”

Section: Methodsmentioning

confidence: 77%

“…The imines and Pd complexes were synthesized according to known methods [8,10]. (1S,2S,5S)-3-(Diphenylmethylimino)2,6,6-trimethylbicyclo[3.1.1]heptan-2-ol (2).…”

Section: Methodsmentioning

confidence: 99%

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New Optically Active CN-Palladacycles Based on 2α-Hydroxypinan-3-One and Camphor Derivatives

et al. 2014

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“…We previously reported the synthesis of chiral imines and amines from 2α-hydroxypinan-3-one [7]. The resulting nitrogen-containing derivatives were successfully used as ligands to obtain various palladium complexes [8,9]. …”

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Stereoselective synthesis of amino ketones of the pinane series

et al. 2015

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SHORT COMMUNICATIONSAt present, enantiomerically pure α-pinene and camphor derivatives are widely used in asymmetric syntheses as chiral auxiliaries [1], building blocks [2,3], and chiral ligands [4]. For example, terpene amino alcohols derived from 2α-hydroxypinan-3-one, were studied as enantioselective ligands in the ruthenium-catalyzed reduction of acetophenone [5], while palladium chelates with bornane diimines and diamines efficiently catalyzed asymmetric allylic substitution reactions [6]. According to published data, search for new enantiomerically pure ligands on the basis of commercially available initial compounds is a topical problem. We previously reported the synthesis of chiral imines and amines from 2α-hydroxypinan-3-one [7]. The resulting nitrogen-containing derivatives were successfully used as ligands to obtain various palladium complexes [8,9].

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Regioselective Short Synthesis of Epiisoborneol Neopentyl Ether as Chiral Auxiliary: An Absolute Configuration Reset

Piątek

Chapuis

2021

Helvetica Chimica Acta

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The regio-selective four step synthesis of (1S,2R,3S,4R)-4,7,7-trimethyl-3-(neopentyloxy)bicyclo[2.2.1]heptan-2ol, as recognized efficient chiral auxiliary, is presented. The strategy based on opening of the key acetal 15 (= (2S,3aR,4S,7R,7aS)-2-tert-butyl-4,8,8-trimethylhexahydro-2H-4,7-methano-1,3-benzodioxole) thus circumvents the poor reactivity of the neopentyl electrophile under alkylation conditions. Following the same strategy, but using the unreported acetal 22 (= (2R,3aS,4S,7R,7aR)-2-tert-butyl-4,8,8-trimethylhexahydro-2H-4,7-methano-1,3benzodioxole), the corresponding unreported bis-endo alcohol 23 (= (1R,2R,3S,4S)-3-(2,2-dimethylpropoxy)-4,7,7trimethylbicyclo[2.2.1]heptan-2-ol) could be isolated only in poor yield. An alternative regioselective synthesis, including an ultimate endo-reduction remains to be found. Several erroneous chiroptical properties from the literature are corrected.

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New chiral cyclopalladated complexes based on the pinane and bornane imines

Cited by 11 publications

References 5 publications

New Optically Active CN-Palladacycles Based on 2α-Hydroxypinan-3-One and Camphor Derivatives

New Optically Active CN-Palladacycles Based on 2α-Hydroxypinan-3-One and Camphor Derivatives

Stereoselective synthesis of amino ketones of the pinane series

Regioselective Short Synthesis of Epiisoborneol Neopentyl Ether as Chiral Auxiliary: An Absolute Configuration Reset

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