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Hou XX, Wei D. Mechanism and Origin of Stereoselectivity for the NHC-Catalyzed Desymmetrization Reaction for the Synthesis of Axially Chiral Biaryl Aldehydes. J Org Chem 2024; 89:3133-3142. [PMID: 38359780 DOI: 10.1021/acs.joc.3c02575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Organocatalytic desymmetrization reaction is a powerful tool for constructing axial chirality, but the theoretical study on the origin of stereoselectivity still lags behind even now. In this work, the N-heterocyclic carbene (NHC)-catalyzed desymmetrization reaction of biaryl frameworks for the synthesis of axially chiral aldehydes has been selected and theoretically investigated by using density functional theory (DFT). The fundamental pathway involves several steps, i.e., desymmetrization, formation of Breslow oxidation, esterification, and NHC regeneration. The desymmetrization and formation of Breslow processes have been identified as stereoselectivity-determining and rate-determining steps. Further weak interaction analyses proved that the C-H···O hydrogen bond and C-H···π interactions are responsible for the stability of the key stereoselective desymmetrization transition states. This research contributes to understanding the nature of NHC-catalyzed desymmetrization reactions for the synthesis of axially chiral compounds.
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Affiliation(s)
- Xiao-Xiao Hou
- College of Chemistry, and Institute of Green Catalysis, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001, Henan, P. R. China
| | - Donghui Wei
- College of Chemistry, and Institute of Green Catalysis, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001, Henan, P. R. China
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Nguyen TH, Pauly C, Kent GT, Wu G, Hayton TW. Dimerization and ring-opening in bis(diisopropylamino)cyclopropenylidene (BAC) mediated by [U(NR 2) 3(CCPh)] (R = SiMe 3). Dalton Trans 2023; 52:13868-13871. [PMID: 37751280 DOI: 10.1039/d3dt02741d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Addition of 2 equiv. of bis(diisopropylamino)cyclopropenylidene (BAC) to [U(NR2)3(CCPh)] (1, R = SiMe3), in Et2O, results in formation of [cyclo-N(iPr)C(Me)2CH(NiPr2)C{CHC3(NiPr2)2}][U(NR2)2(N(SiMe3)SiMe2CH2)(CCPh)] (2) in moderate isolated yield. Complex 2 is the result of coupling and protonation of two BAC molecules, where complex 1 contributes the required proton. It was characterized by NMR spectroscopy and X-ray crystallography and represents a new mode of reactivity of the cyclopropenylidene fragment.
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Affiliation(s)
- Thien H Nguyen
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Christophe Pauly
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Greggory T Kent
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Trevor W Hayton
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
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Liu L, Liu Y, Wu Q, Zhao X, Li Y, Chen G, Bi S. Mechanistic Investigation into the Regio-Controllable Hydroallylations of Alkynes with Allylborons under Pd-Based Synergetic Catalyses. J Org Chem 2023; 88:4536-4545. [PMID: 36930045 DOI: 10.1021/acs.joc.3c00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Density functional theory calculations were employed to investigate the Pd-catalyzed regio-selective hydroallylations of alkynes with allylborons: cooperation of Cu(OAc)2 and dppe resulting in 1,4-dienes while combination of AdCO2H and PCy3 leading to 1,5-dienes. A unified rationalization mechanism called "Lewis-acid-base-interaction promoted deprotonation/3,3-rearrangement" was proposed. Compared with the commonly reported metathesis pathway to only afford the metal-allyl intermediate, in the newly established mechanism, an additional Brønsted acid (as an initiator of the Pd0 oxidative addition) is generated by the interaction of the allylboron (Lewis acid) B atom with the nBuOH (Lewis base) O atom, and subsequent 3,3-rearrangement ensures the thermodynamic feasibility of the reaction. In addition, it was found that excess Cu(OAc)2 plays two potential roles in the oxidative addition/alkyne insertion: (i) the participation of one AcO- of Cu(OAc)2 ensures a large orbital overlap between the migrating H and Pd atoms, facilitating the formal AcO-H cleavage and (ii) the extra (OAc)2Cu···O(carboxyl) σ-coordination indirectly contributes to the (Me)C≡C(Ph) insertion into the Pd-H bond. Further analysis showed that the origin of the regioselectivity is closely related to the employed phosphorus ligand. These revealed results, which have been overlooked in the previous documents, would aid the development of new related catalytic reactions.
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Affiliation(s)
- Lingjun Liu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Yuxia Liu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China.,Shaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Qiao Wu
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
| | - Xufang Zhao
- Shaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Yulin Li
- Key Laboratory of Tibetan Medicine Research and Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai 810001, P. R. China
| | - Guang Chen
- Shaanxi Key Laboratory of Chemical Additives for Industry, College of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.,Key Laboratory of Tibetan Medicine Research and Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai 810001, P. R. China
| | - Siwei Bi
- School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China
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Shyam A, Pradhan AK, Mondal P. Remote N–H activation of indole aldehydes: an investigation of the mechanism, origin of selectivities, and role of the catalyst. NEW J CHEM 2022. [DOI: 10.1039/d1nj05500c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory investigation on the N-heterocyclic carbene-catalysed synthesis of oxazinoindole derivatives via N–H activation of indole aldehydes.
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Affiliation(s)
- Abhijit Shyam
- Department of Chemistry, Assam University, Silchar-788011, Assam, India
| | | | - Paritosh Mondal
- Department of Chemistry, Assam University, Silchar-788011, Assam, India
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