Recent Advances of the Combination of Au/Acid Catalysis

Zhang, Shuo; Fang, Wei; Song, Chuangling; Jia, Jiong; Xu, Zhenghu

doi:10.1002/cjoc.201400428

Cited by 52 publications

(27 citation statements)

References 93 publications

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“…These studies will not be covered, but reviews have been published outlining most of this work [119,120]. Gong et al have demonstrated the coupling of an azlactone, and an alkynol could be achieved by using an achiral phosphine gold methyl complex with an equimolar amount of chiral phosphoric acid (Scheme 30).…”

Section: Scheme 29 Synthesis Of Enantioenriched Bis(indoyl)tetrahydromentioning

confidence: 96%

Enantioselective Gold-Catalyzed Synthesis of Heterocyclic Compounds

Miles

Toste

2015

Topics in Heterocyclic Chemistry

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Asymmetric gold-catalyzed syntheses of a diverse range of heterocycles are described herein. This chapter outlines efforts toward the construction of these molecules via intermolecular, intramolecular, and tandem cyclization strategies. Additionally, asymmetric hydrogenation and epoxidation approaches are detailed. These methodologies generally utilize substrates containing soft, unsaturated carbon-carbon bonds, which can easily interact with the carbophilic gold atom(s). Mostly through the use of bis-or monophosphine ligands, modest to excellent yields and enantioselectivities are obtained for a variety of partially and fully saturated heterocycles. Although steric variation of the phosphine catalyst is the most commonly used strategy for enantioinduction, the use of chiral counteranions has proven useful for more challenging transformations. This chapter includes only examples of syntheses where a chiral gold catalyst is used in the direct formation of the heterocycle; examples of pendant functionalization of an existing heterocycle or chirality transfer from enantioenriched substrate to product are not included.

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Section: Scheme 29 Synthesis Of Enantioenriched Bis(indoyl)tetrahydromentioning

confidence: 96%

Enantioselective Gold-Catalyzed Synthesis of Heterocyclic Compounds

Miles

Toste

2015

Topics in Heterocyclic Chemistry

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“…[1] To date,remarkable progress has been made on organo/metal combined catalysis in the field of asymmetric synthesis. [2] Initiated by independent work by Gong et al and Takemoto and co-workers in 2001, [3] versatile organo/metal dual catalysis systems,s uch as chiral phosphoric acids/Au, [4] aminocatalysts/metal, [5] quinine-based bifunctional molecules/Ag, [6] N-heterocyclic carbene catalysts/metal, [7] and others, [8] have been developed. Form etal/metal combined catalysis,T oste and Corkey discovered ac hiral bisphosphine Pd II /Yb III dual catalyst system for the enantioselective intramolecular Coniaene reaction in 2005.…”

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confidence: 99%

“…Form etal/metal combined catalysis,T oste and Corkey discovered ac hiral bisphosphine Pd II /Yb III dual catalyst system for the enantioselective intramolecular Coniaene reaction in 2005. [9a] In 2010, Hu and co-workers reported ac ooperative catalytic system containing [Rh 2 (OAc) 4 ]a nd (S)-tBu-box-Zn(OTf) 2 for an enantioselective three-component reaction of diazo compounds with water and a,bunsaturated 2-acyli midazoles. [9b] However,t he combination of two metal catalysts for asymmetric reactions was still limited.…”

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confidence: 99%

“…Thesteric hindrance and electronic properties resulting from the incorporation of an aromatic ring on the keto esters had no effect on the efficiencyo ft he cascade reaction. Good yields (70-91 %) with excellent enantioselectivities (> 99 % ee)w ere obtained (entries [4][5][6][7][8][9][10][11][12]. Ring-condensed 1m and heteroaromatic 1n were also suitable substrates, offering 5min 77 %yield and 5nin 83 %yield with more than 99 % ee in both cases (entries [13][14].…”

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confidence: 99%

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Bimetallic Gold(I)/Chiral N,N′‐Dioxide Nickel(II) Asymmetric Relay Catalysis: Chemo‐ and Enantioselective Synthesis of Spiroketals and Spiroaminals

Lin

et al. 2016

Angew Chem Int Ed

124

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A highly efficient asymmetric cascade reaction between keto esters and alkynyl alcohols and amides is reported. The success of the reaction was attributed to the combination of chiral Lewis acid N,N'-dioxide nickel(II) catalysis with achiral π-acid gold(I) catalysis working as an asymmetric relay catalytic system. The corresponding spiroketals and spiroaminals were synthesized in up to 99 % yield, 19:1 d.r., and more than 99 % ee under mild reaction conditions. Control experiments suggest that the N,N'-dioxide ligand was essential for the formation of the spiro products.

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“…但进一步研究发现该类 3H-吡咯化合物不够稳定, 因此, 我们希望以此作为研究的切入点, 将 3H-吡咯转化成更为稳定的有用产物. 本文将在以上工作基础上报道一种结合金与路易斯酸催化的 5-氨基-2H-吡咯的两步合成方法 [9] . 这种合成方为催化剂, 二氯甲烷为溶剂, 室温下反应 6 h 后, 以 85% 产率(76%分离产率)得到相应的 5-氨基-2H-吡咯产物 4a (表 2, Entry 4).…”

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Facile Synthesis of 2H-Pyrroles: Combination of Gold Catalysis and Lewis Acid Catalysis

李新玲¹,

王佳琪²,

李龙³

et al. 2016

Acta Chim. Sinica

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A two-step synthesis of 5-amino 2H-pyrroles using gold and copper catalysis was presented. Firstly, 5-amino 3H-pyrroles were synthesized by gold-catalyzed formal [3＋2] cycloaddition between ynamides and isoxazoles via α-imino gold carbene intermediate. The following Lewis acid-triggered decarbonylation and group migration results in the formation of 5-amino 2H-pyrroles. Other notable features of this method include the simple procedure, the mild reaction conditions and compatibility with a broad range of functional groups. Thus, this protocol provides a practical and general solution for the synthesis of 5-amino 2H-pyrroles. Accordingly, isoxazole 2 (2.0 equiv., 0.6 mmol) and Ph 3 PAuNTf 2 (5 mol%) were added to a suspension of the ynamide 1 (1.0 equiv., 0.3 mmol) in DCM (3.0 mL) at room temperature. The reaction mixture was then stirred at r.t. and the progress of the reaction was monitored by TLC. The reaction typically took 2 h. Upon completion, the mixture was quenched with pyridine, concentrated and purified by chromatography on silica gel, using an eluent of petroleum ether/ethyl acetate (5/1, V/V), to afford 3H-pyrrole 3. Then, 3H-pyrrole 3 and Cu(OTf) 2 (10 mol%) were dissolved in DCM (3 mL) and stirred at room temperature for 6 h. The residue was purified by column chromatography on silica gel, using an eluent of petroleum ether/ethyl acetate (3/1, V/V), to afford the desired 2H-pyrrole 4. Under this condition, a variety of differently substituted ynamides 1 and isoxazoles 2 work well to provide the corresponding 2H-pyrroles 4a～4l in moderate to good overall yields. But N-(4-methoxybenzyl)-N-(phenylethynyl)methanesulfonamide 1a reacts with 4-(3-bromophenyl)-3,5-dimethylisoxazole 2d poorly under this condition, affording product 4h in only 33% yield. These results indicate that this method has certain universality, but the reaction is influenced by the substituents to some extent. Notably, the scalability and preparative utility of the developed methodology was exemplified by the fact that the desired product 4a was obtained without a significant loss in yield when the reaction was scaled up to 5 mmol. Also a plausible mechanism is proposed and we tend to believe that the reaction is featured by an α-imino gold carbene intermediate.

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Recent Advances of the Combination of Au/Acid Catalysis

Cited by 52 publications

References 93 publications

Enantioselective Gold-Catalyzed Synthesis of Heterocyclic Compounds

Enantioselective Gold-Catalyzed Synthesis of Heterocyclic Compounds

Bimetallic Gold(I)/Chiral N,N′‐Dioxide Nickel(II) Asymmetric Relay Catalysis: Chemo‐ and Enantioselective Synthesis of Spiroketals and Spiroaminals

Facile Synthesis of 2H-Pyrroles: Combination of Gold Catalysis and Lewis Acid Catalysis

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