Synthesis of planar chiral [2.2]paracyclophanes by biotransformations: kinetic resolution of 4-formyl-[2.2]paracyclophane by asymmetric reduction

Pamperin, Dirk; Hopf, Henning; Syldatk, Christoph; Pietzsch, Markus

doi:10.1016/s0957-4166(96)00503-4

Cited by 40 publications

(16 citation statements)

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“…[21] However,n one of the applied (S)-or (R)-enantioselective alcohol dehydrogenases suitable for the enantioselective reduction of ab road range of ketones [22] showed activity for acetophenone (M/P)-5,i ndicating that the bulkiness of the TBTQ core hinders its access to the enzymes active site. [23] As an alternative,w ee nvisaged the enzyme class of lipases to potentially tolerate and enantioselectively convert the bulky tribenzotriquinacenes to generate the desired target molecule 7 in enantiomerically and diastereomerically pure form. To this end, first reduction of (M/P)-5 with lithium aluminum hydride was carried out to give the corresponding secondary benzylic alcohols as am ixture of four stereoisomers (diastereomeric racemates), (M/P,R/S)-7,i naratio of 1:1:1:1, as revealed by chromatography on ac hiral support.…”

Section: Thepolycyclicmolecularframeworkoftribenzotriquinacenementioning

confidence: 99%

Enantiomerically Pure Tribenzotriquinacenes through Stereoselective Synthesis

et al. 2015

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Inherently chiral acetophenones and benzaldehydes bearing the large, bowl-shaped framework of tribenzotriquinacene (TBTQ) were synthesized in enantiomerically pure form employing enzyme catalysis. Five-step sequences involving lipase CAL-B lead to the (M)-enantiomers, (+)-2-acetyl-TBTQ (M)-5 and (+)-2-formyl-TBTQ (M)-6, whereas use of lipase PS leads to the (P)-enantiomers, (-)-2-acetyl-TBTQ (P)-5 and (-)-2-formyl-TBTQ (P)-6, with at least 99% ee in each case. The absolute configuration of these rigid 3D building blocks was determined by X-ray diffraction analysis of the ketones 5 and by comparison of their chiroptical properties with those of the aldehydes 6.

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Section: Thepolycyclicmolecularframeworkoftribenzotriquinacenementioning

confidence: 99%

Enantiomerically Pure Tribenzotriquinacenes through Stereoselective Synthesis

et al. 2015

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“…All coupling constants are absolute values. 13 C NMR: Bruker AM 400 (100 MHz), Bruker DRX 500 (125 MHz); d ¼ 77.00 ppm for CHCl 3 . IR: KBr pellets on a Bruker IFS88 IR; EI-HR-MS: Thermo Quest Finnegan MAT 90 (70 eV).…”

mentioning

confidence: 99%

Planar‐ and Central‐Chiral N,O‐[2.2]Paracyclophane Ligands: Non‐Linear‐Like Effects and Activity

Lauterwasser¹,

Vanderheiden²,

Bräse³

2006

Adv Synth Catal

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The non-linear-like effect (NLLE), activity, temperature dependence, and kinetics of hydroxy-[2.2]paracyclophane ketimine ligands have been investigated with the 1,2-addition reaction of diethylzinc to cyclohexanecarbaldehyde. A linear correlation between the enantiomeric excess of AHPC ketimine ligands bearing a phenylethyl side group and the product was observed with 0.5 mol % of catalyst loading. On increasing the catalyst loading to 4 mol %, a precipitate of the inactive heterochiral species was formed and resulted in a positive nonlinear-like effect. The enantiomeric ratio was found to have linear temperature dependence.Keywords: asymmetric catalysis; catalytic activity; non-linear-like effect; paracyclophanes Asymmetric catalysis often displays a relationship between selectivity and reactivity. Intricate molecular mechanisms with a number of rate constants often lead to complex rate laws. The latter have not been elucidated in most cases although attempts have been made to unravel them.[1] Features such as non-linear effects, [2] autocatalysis, [3] reservoir effects, chiral poisoning, [4] and asymmetric activation [5] have been discovered in asymmetric catalytic reactions.[6] In particular, the strong non-linear effect associated with Noyoris DAIB ligand in the addition of diethylzinc to benzaldehyde has been thoroughly investigated.[7a]Since the initial reports of Reich and Cram, [8] the field of [2.2]paracyclophane chemistry has grown considerably.[9] The chemical behavior of [2.2]paracyclophanes is currently well understood allowing predictable modification of this relatively stable class of molecules. [10 -13] Within the last few years, various new paracyclophane ligands have been used for asymmetric catalysis. [14 -17] In particular, the asymmetric 1,2-addition reaction of zinc reagents [18] such as alkyl, [19 -21] alkenyl, [22] aryl [23] and alkynyl [24] zinc reagents with aldehydes or imines, [19,20,23] can be efficiently controlled by the application of hydroxy[2.2]paracyclophane ketimine ligands.[17]We recently reported the synthesis of the [2.2]paracyclophane-based ketimine ligands (R P ,S)-2, (S P ,S)-2, (R P ,S)-3, and (S P ,S)-3 and their application in asymmetric catalysis such as the addition of zinc reagents to aldehydes. [19] During these studies, we observed not only that these ligands are highly active, [21,25] but also that they display mismatched and matched cases. [19,22] In general, the [2.2]paracyclophane backbone determines the configuration of the product. However, it was possible to finetune the ligand system by adjusting the side groups.The successful applications of these [2.2]paracyclophane-based ligands led to further investigations of this system. In this manuscript, we disclose our findings which lead to a deeper understanding of this ligand class. We present studies of the non-linear-like effect (NLLE) [26] with the enantiomeric pairs 1 and 3, respectively. In addition, we investigated the activity of the diastereomers (R P ,S)-2 and (S P ,S)-2 and the diaste...

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“…In 1997, Pietzsch and coworkers demonstrated that also [2.2]paracyclophanes can be used as substrates in bioreductions performed by baker's yeast. 121 Following up on a preliminary study by Izumi and Hinata, 92 ten different microorganisms as well as isolated alcohol dehydrogenases were evaluated as biological catalysts for the selective reduction of 2-formyl-[2.2]paracyclophane (128) and while all microbial whole cell systems provided activity, a baker's yeast strain (S. cerevisiae DSM 11285) was identified as most enantioselective reducing agent. Hence, after co-fermentation of rac-128 the planar chiral aldehyde was re-isolated in excellent optical purity (Scheme 58).…”

Section: Scheme 56mentioning

confidence: 99%

Enzymatic approaches for the preparation of optically active non-centrochiral compounds

2016

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Synthesis of planar chiral [2.2]paracyclophanes by biotransformations: kinetic resolution of 4-formyl-[2.2]paracyclophane by asymmetric reduction

Cited by 40 publications

References 15 publications

Enantiomerically Pure Tribenzotriquinacenes through Stereoselective Synthesis

Enantiomerically Pure Tribenzotriquinacenes through Stereoselective Synthesis

Planar‐ and Central‐Chiral N,O‐[2.2]Paracyclophane Ligands: Non‐Linear‐Like Effects and Activity

Enzymatic approaches for the preparation of optically active non-centrochiral compounds

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