Chiral Copper(II)‐Catalyzed Enantioselective Boron Conjugate Additions to α,β‐Unsaturated Carbonyl Compounds in Water

Kobayashi, Shū; Xu, Pengyu; Endo, Toshimitsu; Ueno, Masaki; Kitanosono, Taku

doi:10.1002/ange.201207343

Cited by 48 publications

(12 citation statements)

References 73 publications

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“…While using 1-(trifluoromethyl)alkenes (1, R = (hetero)aryl) such as 1w-1x as substrates, C-Cu bond formation may be electronically favored at the benzylic position stabilization by the (hetero)aryl group (C 0 ). [57][58][59][60][61][62] After further enantioselective formation of intermediate D, cis b-F elimination [33][34][35][36][37][38][39][40][45][46][47][48][49] delivers the final product 3 and a CuF-like species E, which can undergo anion exchange with NaO t Bu to regenerate the copper catalyst.…”

Section: Resultsmentioning

confidence: 99%

Copper-Catalyzed Asymmetric Defluoroborylation of 1-(Trifluoromethyl)Alkenes

Gao

Yuan

Zhao

et al. 2018

Chem

143

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gem-Difluoroalkenes have steric and electronic profiles similar to those of ketones, aldehydes, and esters, and consequently have been used widely as carbonyl isosteres in modern drug discovery. Although many attempts have been made to achieve gem-difluoroalkenes, the induction of enantioselectivity at the a position of a gem-difluorovinyl group still remains a challenge. Herein, an efficient method for the construction of gem-difluoroallylboronates with high enantiomeric excess via a copper-catalyzed defluoroborylation of 1-(trifluoromethyl)alkenes with B 2 pin 2 is described. The reaction conditions were mild, and a variety of common functional groups, such as ether, fluoride, chloride, bromide, iodide, ester, cyano, sulfide, amino, and indoyl groups, were well tolerated. Furthermore, we not only applied this developed system as a powerful synthetic tool for the late-stage modification of complex compounds but also highlighted the utility of the formed compounds in synthesis.

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Section: Resultsmentioning

confidence: 99%

Copper-Catalyzed Asymmetric Defluoroborylation of 1-(Trifluoromethyl)Alkenes

Gao

Yuan

Zhao

et al. 2018

Chem

143

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“…These results clearly indicate the retainment of structural integrity and that Cu3(BTC)2 is highly stable under the present experimental conditions. In an earlier precedent, Kobayashi and co-workers proposed a reaction mechanism involving the cleavage of the B-B bond by the base, forming pinacolyl borate and a nucleophilic boronate species that becomes coordinated to the Cu site [19]. Subsequently, the coordination of α,β-enone to the Cu atom and transfer of the Bpin moiety from the Cu 2+ ion to the β-carbon would render the final product and would restore the catalytically active Cu species.…”

Section: Resultsmentioning

confidence: 99%

“…This organic transformation was reported with a series of homogeneous catalysts consisting of transition metals such as Pt [7,8], Rh [9], Cu [10][11][12][13], Ni [14], N-heterocyclic carbenes [15,16], and Brönsted bases [17]. In this regard, it has been recently reported that 2-cyclohexenone can react with B 2 pin 2 in the presence of metallic Cu, Cu(I) or Cu(II) salts or complexes to obtain β-ketopinacolboronates [18][19][20][21][22][23]. Although homogeneous copper salts or complexes have been reported for this reaction [23], examples on the use of heterogeneous copper-based catalysts are still limited.…”

Section: Introductionmentioning

confidence: 90%

α,β-Enone Borylation by Bis(Pinacolato)Diboron Catalyzed by Cu3(BTC)2 Using Cesium Carbonate as a Base

et al. 2021

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Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylate) as a heterogeneous catalyst in the presence of cesium carbonate as a base is reported for the borylation of α,β-conjugated enones by bis(pinacolato)diboron (B2pin2). According to the hot-filtration test, Cu3(BTC)2 is acting as a heterogeneous catalyst. Further, Cu3(BTC)2 exhibits a wide substrate scope and can be reused in consecutive runs, maintaining a crystal structure as evidenced by powder X-ray diffraction (XRD). A suitable mechanism is also proposed for this transformation using Cu3(BTC)2 as catalyst.

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“…7). Optically pure 5o was obtained through Cu-catalyzed enantioselective 1,4-borylation of the sorbic acid-derived ester 69,70 . Diastereoselective α-allylation of chiral 5o with standard conditions and subsequent oxidation with NaBO 3 furnished 17 and 20 in good yields.…”

Section: Resultsmentioning

confidence: 99%

A unified approach for divergent synthesis of contiguous stereodiads employing a small boronyl group

Zhan

Ding

et al. 2020

Nat Commun

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Acyclic contiguous stereocenters are frequently seen in biologically active natural and synthetic molecules. Although various synthetic methods have been reported, predictable and unified approaches to all possible stereoisomers are rare, particularly for those containing non-reactive hydrocarbon substituents. Herein, a β-boronyl group is employed as a readily accessible handle for predictable α-functionalization of enolates with either syn or anti selectivity depending on reaction conditions. Contiguous tertiary-tertiary and tertiaryquaternary stereocenters are thus accessed in generally good yields and diastereoselectivity. Based on experimental and computational studies, mechanism for syn selective alkylation is proposed, and Bpin (pinacolatoboronyl) behaves as a smaller group than most carboncentered groups. The synthetic utility of this methodology is demonstrated by preparation of several key intermediates for bioactive molecules.

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Chiral Copper(II)‐Catalyzed Enantioselective Boron Conjugate Additions to α,β‐Unsaturated Carbonyl Compounds in Water

Cited by 48 publications

References 73 publications

Copper-Catalyzed Asymmetric Defluoroborylation of 1-(Trifluoromethyl)Alkenes

Copper-Catalyzed Asymmetric Defluoroborylation of 1-(Trifluoromethyl)Alkenes

α,β-Enone Borylation by Bis(Pinacolato)Diboron Catalyzed by Cu3(BTC)2 Using Cesium Carbonate as a Base

A unified approach for divergent synthesis of contiguous stereodiads employing a small boronyl group

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