Highly Stereoselective Synthesis of Novel Multistereogenic Bis<i>-</i>Bifunctional Ligands Based on [2.2]Paracyclophane- 4,7-quinone, their Structure Elucidation and Application in Asymmetric Catalysis

Vorontsova, N. V.; Воронцов, Е. В.; Antonov, Dmitrii Yu.; Starikova, Z. A.; Butin, K. P.; Bräse, Stefan; Höfener, Sebastian; Rozenberg, V. I.

doi:10.1002/adsc.200404200

Cited by 13 publications

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“…[2.2]Paracyclophane‐derived quinones, quinhydrones, and their esters were traditionally used as attractive models to investigate the dependence of donor–acceptor (D‐A) interactions with respect to the mutual arrangement of the D and A substituents 14. Multistereogenic bis‐bifunctional ligands 15 , obtainable by stereoselective addition of organolithium compounds to enantiomers of [2.2]paracyclophane‐4,7‐quinone ( 14 ),15 were applied as chiral ligands in the asymmetric diethylzinc addition to aldehydes 15b. Recently, the respective para ‐ditriflate obtained from ( S p)‐ 14 was found to be a suitable precursor for the synthesis of diaryl derivatives ( S p)‐ 16 by double Suzuki coupling16 (Figure 3).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Bromo‐Substituted 4‐Hydroxy[2.2]paracyclophanes and [2.2]Paracyclophane‐4,7‐quinones as Versatile Chiral Building Blocks

et al. 2014

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Section: Resultsmentioning

confidence: 99%

Synthesis of Bromo‐Substituted 4‐Hydroxy[2.2]paracyclophanes and [2.2]Paracyclophane‐4,7‐quinones as Versatile Chiral Building Blocks

et al. 2014

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“…In such ligands the hydroxy groups, bound to the [2.2]paracyclophane scaffold and arranged pairwise with functional groups of the aryl fragments, form two independent systems, both of which are capable of coordination with a metal or metal containing fragment. These compounds function as chiral inductors in the enantioselective addition of diethylzinc to benzaldehyde (up to 93.5 % ee ) 15b…”

Section: Introductionmentioning

confidence: 99%

Symmetrically Tetrasubstituted [2.2]Paracyclophanes: Their Systematization and Regioselective Synthesis of Several Types of Bis‐Bifunctional Derivatives by Double Electrophilic Substitution

Vorontsova

Rozenberg

Сергеева

et al. 2008

Chemistry A European J

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The possible number of chiral and achiral tetrasubstituted [2.2]paracyclophanes possessing different types of symmetry (C(2), C(i), C(s), C(2v), C(2h)) is evaluated and a unified independent trivial naming descriptor system is introduced. The reactivity and regioselectivity of the electrophilic substitution of the chiral pseudo-meta- and achiral pseudo-para-disubstituted [2.2]paracyclophanes are investigated in an approach suggested to be general for the synthesis of bis-bifunctional [2.2]paracyclophanes. The mono- and diacylation of chiral pseudo-meta-dihydroxy[2.2]paracyclophane 14 with acetylchloride occur ortho-regioselectively to produce tri- 22, 23 and symmetrically 21 tetrasubstituted acyl derivatives. The same reaction with benzoylchloride is neither regio-, nor chemoselective, and gives rise to a mixture of ortho-/para-, mono-/diacylated compounds 27-31. The double acylation of pseudo-meta-dimethoxy[2.2]paracyclophane 18 is completely para-regioselective. Electrophilic substitution of pseudo-meta-bis(methoxycarbonyl)[2.2]paracyclophane 20 regioselectively generates the pseudo-gem-substitution pattern. Formylation of this substrate produces the monocarbonyl derivatives 35 only, whereas the Fe-catalyzed bromination may be directed towards mono- 36 or disubstitution 37 products chemoselectively by varying the reactions conditions. The diacylation and dibromination reactions of the respective achiral diphenol 12 and bis(methoxycarbonyl) 40 derivatives of the pseudo-para-structure retain regioselectivities which are characteristic for their pseudo-meta-regioisomers. Imino ligands 26, 25, and 39, which were obtained from monoacyl- 22 and diacyldihydroxy[2.2]paracyclophanes 21, 38, are tested as chiral ligands in stereoselective Et(2)Zn addition to benzaldehyde producing 1-phenylpropanol with ee values up to 76 %.

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Second‐Generation N,O‐[2.2]Paracyclophane Ketimine Ligands for the Alkenylzinc Addition to Aliphatic and Aromatic Aldehydes: Scope and Limitations

et al. 2006

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Second generation N,O-[2.2]paracyclophane ketimine ligands were investigated for their ability to catalyze the 1,2-addition of alkenylzinc reagents to aliphatic and aromatic aldehydes with special focus on functionalized substrates. For aliphatic aldehydes, which have always been challenging in this field, remarkably high enantiomeric excesses could be determined (50-95 % ee). However, alkenylzinc reagents bearing heteroatoms proved to be demanding substrates for this system. Keywords: alkenylzinc reagents; asymmetric catalysis; chiral allylic alcohols; N,O ligands; paracyclophanes Chiral allylic alcohols are important targets in organic synthesis, especially in natural product synthesis. As intermediates they can be used in further reactions such as allylic substitution, dihydroxylation, ene reaction, cyclopropanation, bromination, or epoxidation. However, the lack of a powerful ligand system impedes the use of the 1,2-addition of alkenylzinc reagents to aldehydes as a key step in natural product synthesis because highly functionalized substrates must be tolerated and high enantiomeric excesses must be achieved.[1] The rare examples in the literature show mostly the use of divinylzinc and substrateinduced diastereoselectivity. [2] In the case of substrate toleration, the catalyzed alkenylzinc addition could be an appropriate method because of the relatively low reactivity of zinc diorganyls towards aldehydes and ketones in comparison to other organometal compounds.[3] However, investigations in this field are few. In contrast, alkyl transfer to aromatic aldehydes is one of the most studied enantioselective catalytic reactions, yet there are only a few examples with high enantiomeric excesses for aliphatic aldehydes.[4] The alkenylzinc transfer is even less investigated; however, interest in this reaction has increased throughout the last years. [5][6][7][8][9][10][11][12] One method elaborated by Oppolzer and Radinov produces mixed alkyl-alkenylzinc species in situ using a transmetalation protocol involving hydroboration of alkynes.[2]paracyclophane-based ligands produce results ranging from good to excellent for this type of reaction, whereas the scope is limited to aromatic aldehydes and fully branched aliphatic aldehydes.[11] Wipf et al. also reported the preparation of alkenylzinc reagents via transmetalation but using zirconium as metal. [9] A comprehensive survey of [2.2]paracyclophanebased ligands can be found in recent reviews.[13] The use of planar-chiral and central-chiral ligands based on paracyclophane systems has emerged en masse since the disclosures by Belokon, Rozenberg et al., [14,15] the Berkessel group, [16] and most notably the Hopf group.[17] Within the last years, various new paracyclophane ligands have been used for asymmetric catalysis. [18][19][20] In particular, the asymmetric 1,2-addition reaction of organozinc compounds such as alkyl-, [21] alkenyl-, [11] and alkynylzinc [22] reagents with aldehydes or imines, [21] respectively, can be efficiently controlled by the use of...

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Highly Stereoselective Synthesis of Novel Multistereogenic Bis-Bifunctional Ligands Based on [2.2]Paracyclophane- 4,7-quinone, their Structure Elucidation and Application in Asymmetric Catalysis

Cited by 13 publications

References 8 publications

Synthesis of Bromo‐Substituted 4‐Hydroxy[2.2]paracyclophanes and [2.2]Paracyclophane‐4,7‐quinones as Versatile Chiral Building Blocks

Synthesis of Bromo‐Substituted 4‐Hydroxy[2.2]paracyclophanes and [2.2]Paracyclophane‐4,7‐quinones as Versatile Chiral Building Blocks

Symmetrically Tetrasubstituted [2.2]Paracyclophanes: Their Systematization and Regioselective Synthesis of Several Types of Bis‐Bifunctional Derivatives by Double Electrophilic Substitution

Second‐Generation N,O‐[2.2]Paracyclophane Ketimine Ligands for the Alkenylzinc Addition to Aliphatic and Aromatic Aldehydes: Scope and Limitations

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