Gold-Catalyzed Reaction of Propargylic Carboxylates via an Initial 3,3-Rearrangement

Wang, Shaozhong; Zhang, Guozhu; Zhang, Liming

doi:10.1055/s-0029-1219527

Cited by 62 publications

(10 citation statements)

References 8 publications

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“…Acetates derived from primary/secondary propargylic alcohols with various substitution patterns and containing different functional groups were all allowed, although the tertiary counterpart underwent gold-catalyzed 3,3-rearrangement preferentially [21] and hence was not a viable substrate. Except entry 7, the gold-catalyzed oxidations proceeded with excellent regioselectivities (>25:1), and the desired α-acyloxy α,β-unsaturated ketones/aldehyde were isolated with fair to excellent yields.…”

Section: Resultsmentioning

confidence: 99%

“…We reported previously that synthetically useful regioselectivity could be achieved if the two ends of the C–C triple bond are biased by a steric bulk and/or via conjugation (Scheme 2). In our continued effort to reveal regioselectivities of this oxidation with different types of internal alkynes, we examined propargylic carboxylates, which have served as a versatile platform for the development of a diverse range of gold catalysis [21]. Herein we report our findings and the development of a reliable synthesis of α-carboxy α,β-unsaturated ketones/aldehydes.…”

Section: Introductionmentioning

confidence: 99%

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Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

Ji¹,

Nelson²,

Zhang³

2013

Beilstein J. Org. Chem.

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SummaryGold-catalyzed intermolecular oxidation of carboxylates of primary or secondary propargylic alcohols are realized with excellent regioselectivity, which is ascribed to inductive polarization of the C–C triple bond by the electron-withdrawing carboxy group. The gold carbene intermediates thus generated undergo selective 1,2-acyloxy migration over a 1,2-C–H insertion, and the selectivities could be dramatically improved by the use of a P,S-bidentate ligand, which is proposed to enable the formation of tris-coordinated and hence less electrophilic gold carbene species. α-Carboxy α,β-unsaturated ketones/aldehydes can be obtained with fair to excellent yields.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

Ji¹,

Nelson²,

Zhang³

2013

Beilstein J. Org. Chem.

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“…Intramolecular migration of the acetoxy group in gold catalysis, which typically involves 1,2- or 1,3-migration of a propargyl ester, has been the subject of considerable studies in recent years. , Gold-catalyzed cyclization of 1,7-enynes with propargylic acetates leads to tricyclic derivatives usually with high stereoselectivity . Hanna utilized this strategy in the synthesis of the seven-membered benzofused tricyclic compound 132 starting from the propargylic acetate 131 , Scheme , in their work toward the synthesis of a new class of allocolchinoids .…”

Section: Direct Ring Formationmentioning

confidence: 99%

Construction of Medium-Sized Rings by Gold Catalysis

2020

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Compounds having cyclic molecular frameworks are highly regarded for their abundance and diverse utilities. In particular, medium-sized carbocycles and heterocycles exist in a broad spectrum of natural products, bioactive therapeutics, and medicinally significant synthetic molecules. Metal-mediated methods have been developed for the preparation of compounds containing a medium-sized ring (MSR) through cyclization of different classes of substrates and acyclic precursors. This review focuses on the methodologies for construction of MSRs via gold catalysis. Given the challenges in enabling the assembly of different ring sizes, we present here accounts on Au-mediated cyclization giving notable 7-membered and medium-sized (8–11-membered ring) structures. Emphasis on the pathway and mode of cyclization and the selection of precursors ranging from structurally biased compounds were outlined. Reactivity patterns and the choice of efficient Au catalysts for controlling reaction performance and selectivity in addition to mechanistic attributes are examined.

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“…Following this seminal discovery, the field has experienced an exponential increase in attention that has led to the realization of a myriad of elegant methods to prepare a wide variety of synthetic targets from the substrate class. − In general, the modes of reactivity of propargyl ester 11 reported in these studies were found to be initiated by either a gold-mediated [2,3]- or [3,3]-sigmatropic rearrangement pathway (Scheme ). The syn 1,2-acyloxy migration pathway was shown to comprise of the 5- exo - dig cyclization and cycloreversion of the gold-coordinated propargyl ester 12 to give the gold-carbene intermediate 14 via the 1,3-dioxol-1-ium species 13 (Scheme , path a ).…”

Section: Discovery Of the Two Key Modes Of Propargyl Ester Reactivitymentioning

confidence: 99%

Recent Advances in the Gold-Catalyzed Reactions of Propargyl Esters

2023

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Conspectus Late-transition-metal-based complexes represent an indispensable catalytic tool in chemical synthesis due to their ability to increase molecular complexity rapidly and efficiently from readily accessible substrates in a single operation. Added to this is the exquisite control of product chemo-, diastereo-, enantio-, and site-selectivities achieved by catalytic systems of the transition-metal salts that have been developed to mediate a wide range of functional group transformations. Within this venerable synthetic toolbox, complexes and salts of Au(I) and Au(III) have emerged in recent years as an invaluable addition as a result of their potent σ- and π-Lewis acidities and ability to stabilize cationic reaction intermediates. The insights provided by mechanistic studies examining the various electronic, steric, and stereoelectronic factors at play in the organogold species that are expected to be formed in the catalytic chemistry of the transition-metal complex have also been pivotal in understanding and exploring their potential synthetic utility. Illustrative of this, for example, is the contribution made by the gold-catalyzed cycloisomerization chemistry of propargyl esters in synthetic strategies to a variety of bioactive natural products and compounds of current pharmaceutical and materials interest. This Account summarizes our efforts over the past decade toward realizing new single-step strategies for carbocyclic and heterocyclic synthesis that relied on the gold-catalyzed reactions of propargyl esters. It outlines synthetic methods developed by the group that exploited the unique reactivities of the gold-carbene species typically generated from the [2,3]-sigmatropic rearrangement of the compound class containing a terminal or electron-deficient alkyne moiety on exposure to the transition-metal salt. This Account also describes the realization of synthetic methods initiated by the gold-catalyzed 1,3-acyloxy migration of propargyl esters with an electronically unbiased disubstituted CC bond that delivers the corresponding allenyl ester that is primed for further reactivity on activation by the group 11 metal complex. The studies formed a part of an ongoing overarching program within our group that was focused on determining reactivities in gold catalysis that would enable their application as readily recognizable disconnections in retrosynthetic analysis. They were additionally a part of efforts aimed at evaluating the opportunities offered by the relativistic effects possessed by a Au(I) and Au(III) complex, the most pronounced among the d-block elements and thus the catalyst of choice in alkyne activation chemistry, to generate new chemical space. For instance, we demonstrated in several studies the cycloisomerization of 1,3- and 1,4-enyne esters to be a reliable strategy for the in situ formation of a wide range of 1,4-cyclopentadienyl derivatives. Their further reaction with an appropriately placed functional group or a second starting material was then shown to afford a variety of synthe...

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Gold-Catalyzed Reaction of Propargylic Carboxylates via an Initial 3,3-Rearrangement

Abstract: Gold-catalyzed 3,3-rearrangement of propargylic carboxylates offers a versatile entry into a range of fascinating subsequent transformations, leading to various functional structures.

Cited by 62 publications

References 8 publications

Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

Gold-catalyzed regioselective oxidation of propargylic carboxylates: a reliable access to α-carboxy-α,β-unsaturated ketones/aldehydes

Construction of Medium-Sized Rings by Gold Catalysis

Recent Advances in the Gold-Catalyzed Reactions of Propargyl Esters

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