C‐H‐Funktionalisierung durch eine intramolekulare Redox‐Strategie

Jurberg, Igor D.; Peng, Bo; Wöstefeld, Eckhard; Wasserloos, Maximilian; Maulide, Nuno

doi:10.1002/ange.201108639

Cited by 42 publications

(16 citation statements)

References 47 publications

(26 reference statements)

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“…Secondly, to date, there has been no experimental evidence or theoretical investigation regarding the proton-transfer pathway or its stereochemical features in a catalyzed process. [9] In addition, it remains unclear how a rate-limiting 1,5-H transfer dictates the subsequent stereochemistry-generating C À X bond-formation step. Herein, we report our detailed computational investigations, as well as experimental studies, with the aim of addressing these mechanistic puzzles.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies of the Asymmetric Binary‐Acid‐Catalyzed tert‐Aminocyclization Reaction: Origins of the CH Activation and Stereoselectivity

Zhang

Chen

et al. 2012

Chemistry An Asian Journal

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A mechanistic study of the tert-aminocyclization reaction was performed by using DFT calculations and labeling experiments. The results showed that the reaction proceeded through a rate-limiting-, stereospecific-, and suprafacial 1,5-H-transfer pathway, followed by a barrier-less C-C bond formation. The mode of stereocontrol for facial selection could be ruled out owing to the high activation energy of C-N bond rotation. The intrinsic feature of this Lewis acid activation was found to be the activation of the LUMO, as well as an intermediate-stabilization effect. The catalytically active species was believed to be a 1:1 complex of phosphoric acid and MgCl(2), which was stabilized by a H⋅⋅⋅Cl hydrogen bond. The chiral catalytic complex selectively recognizes and activates one of the two helical conformations of substrate A, required for 1,5-suprafacial H-transfer, which dictates the stereoselectivity of the forming products.

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Section: Introductionmentioning

confidence: 99%

Theoretical Studies of the Asymmetric Binary‐Acid‐Catalyzed tert‐Aminocyclization Reaction: Origins of the CH Activation and Stereoselectivity

Zhang

Chen

et al. 2012

Chemistry An Asian Journal

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“…Mechanistically, this process involves a [1,5]-hydride shift, catalyzed by Lewis or Brønsted acids, which have attracted much attention lately. [9] Herein, we would like to report on the synthesis of geometrically pure allylic b,b-dichloroamines by using a Lewis acid promoted reaction between a,a-dichloroaldimines and terminal alkynes. The reaction mechanism and feasibility of the vinylation process was supported by quantum mechanical calculations.…”

Section: Introductionmentioning

confidence: 99%

Lewis Acid Mediated Vinyl‐Transfer Reaction of Alkynes to N‐Alkylimines by Using the N‐Alkyl Residue as a Sacrificial Hydrogen Donor

Malakar

Stas

Herrebout

et al. 2013

Chemistry A European J

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A variety of N-alkyl-α,α-dichloroaldimines were vinylated by terminal acetylenes in the presence of Lewis acids such as In(OTf)3 or BF3 ⋅OEt2 and hexafluoroisopropanol (HFIP) as an additive. The reaction proceeds at ambient temperature and leads to geometrically pure allylic β,β-dichloroamines. This approach is complementary to previously reported transition-metal-catalyzed vinyl-transfer methods, which are not applicable to aliphatic imines and are restricted to imines that contain an electron-withdrawing nitrogen substituent. In the present approach, terminal alkynes were used as a source of the vinyl residue, and the N-alkyl moiety of the imine acts as a sacrificial hydrogen donor. The additional advantage of this methodology is the fact that no external toxic or hazardous reducing agents or molecular hydrogen has to be used. This new methodology nicely combines a C(sp(2) )C(sp) bond formation, hydride transfer, and an unusual cleavage of an unactivated CN bond, thereby giving rise to functionalized primary allylic amines. A detailed experimental study supported by DFT calculations of the mechanism has been done.

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“…[16] More recently we also showed that the generation of vinamidinium intermediates [17] arising from 1,3-propanediols and amines led to various julolidines through an electrocyclization/b-alkylation sequence. [18] Herein we disclose the applicationo fo ur catalytic systems with the use of 2-hydroxybenzaldehyde derivatives and cyclic tertiary amines to afford straightforward access to the corresponding functionalized cyclic hemiaminal ethers [19] by vicinal a,b-difunctionalization. The unprecedented formationo fa-alkylatedl actamsf rom the starting tertiaryc yclic amines is also successfully achieved by af ormal endo-cyclic dehydrogenative hydrolysis involving the iminium intermediates ( Figure 1).…”

mentioning

confidence: 99%

Vicinal α,β‐Functionalizations of Amines: Cyclization Versus Dehydrogenative Hydrolysis

Jiang

Achard

Bruneau

2015

Chemistry A European J

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C‐H‐Funktionalisierung durch eine intramolekulare Redox‐Strategie

Cited by 42 publications

References 47 publications

Theoretical Studies of the Asymmetric Binary‐Acid‐Catalyzed tert‐Aminocyclization Reaction: Origins of the CH Activation and Stereoselectivity

Theoretical Studies of the Asymmetric Binary‐Acid‐Catalyzed tert‐Aminocyclization Reaction: Origins of the CH Activation and Stereoselectivity

Lewis Acid Mediated Vinyl‐Transfer Reaction of Alkynes to N‐Alkylimines by Using the N‐Alkyl Residue as a Sacrificial Hydrogen Donor

Vicinal α,β‐Functionalizations of Amines: Cyclization Versus Dehydrogenative Hydrolysis

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