Lewis Acid Catalyzed Intramolecular [4+2] and [3+2] Cross‐Cycloaddition of Alkynylcyclopropane Ketones with Carbonyl Compounds and Imines

Bai, Yu; Tao, Weijie; Ren, Jing; Wang, Zhongwen

doi:10.1002/anie.201200450

Cited by 100 publications

(14 citation statements)

References 143 publications

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“…Upon extension of this reaction pattern, in 2012, Wang and co-workers discovered a general strategy for stereoselective construction of bridged oxa-/aza-[ n .3.1] 226 and oxa-/aza-[ n .2.1] 227 skeletons, which widely exist in natural products (Scheme ). By prudent selection of the Lewis acids based on their π-electrophilic (gold catalyst) and σ-electrophilic (nickel catalyst) properties, controllable [4+2] and [3+2] cross-cycloadditions of carbonyl group tethered alkynylcyclopropane ketones 225 could be achieved.…”

Section: Gold-catalyzed Intramolecular Reactions Of Functionalized Al...mentioning

confidence: 99%

Gold-Catalyzed Conversion of Highly Strained Compounds

Zang

Bird

et al. 2020

Chem. Rev.

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The past decade has witnessed the golden age of homogeneous gold-catalyzed reactions, especially those that involve the transformation of highly strained molecules into complex molecular architectures. Gold catalysts, with unique electronic properties and catalytic abilities, have elevated versatile reaction modes through π-interaction induced activation. On the basis of increasing research interest in this topic, together with the significant development of various ligands, including phosphine ligands and azacyclic or noncyclic carbene ligands, the understanding of the catalytic function of gold catalysts has become much deeper and more comprehensive. Different reaction needs thus could be adapted by a novel gold catalyst with a diversified ligand selection. Furthermore, the whole evolution of the gold catalysis on synthetic methodologies has realized and expanded its application into natural product synthesis as well as the potentiality of drug discovery, which endows this ancient metal with a magnificent renaissance. The reactivity of strained small ring molecules with high tension has always been an important research topic in organic chemistry. When the highly strained small ring is linked with a π-electron rich moiety or contains a heteroatom, the gold activation of the π-system or coordination with the heteroatom can initiate a cascade reaction, usually followed by ring opening or expansion. These processes can result in the rapid construction of complex and distinct molecular structures, many of which feature in biologically important molecules. In this review, we will mainly summarize the advances on diverse reaction types and molecular constructions accomplished by homogeneous gold catalysis using highly strained substrates, including methylenecyclopropanes (MCPs), vinylidenecyclopropanes (VDCPs), cyclopropenes as well as aziridine- and epoxide-containing molecules, focusing on the last 10 years. For functionalized alkynyl cyclopropanes, several early inspiring and elegant examples will be described in this review for systematically understanding these transformations.

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Section: Gold-catalyzed Intramolecular Reactions Of Functionalized Al...mentioning

confidence: 99%

Gold-Catalyzed Conversion of Highly Strained Compounds

Zang

Bird

et al. 2020

Chem. Rev.

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“…Similarly, these authors described novel intramolecular [4+2] and [3+2] cross-cycloaddition (IMCC) reactions of carbonyl-or imine-containing alkynylcyclopropane ketones for the synthesis of oxa and aza[n.2.1]alkane bridged systems. 11 As an example, the preparation of oxa[3.2.1]octane systems is shown in Scheme 3.…”

Section: Figurementioning

confidence: 99%

“…It was found that compound 9 captures electrons and rapidly loses a bromide ion to give the corresponding C8 radical 10. This radical abstracts a hydrogen atom intramolecularly, from the C5′ position exclusively, to afford selectively a C5′ radical (11). This discovery allowed, for the first time, a proper study of the fate of the 2′-deoxyadenosin-5′-yl radical, and in particular the cyclization step at C5′ and C8, which occurs with a constant rate of 1.60•10 5 s -1 and leads to N7 radical 12, and then finally produces the 5′,8-cyclo-2′-deoxyadenosine.…”

Section: Cyclonucleotidesmentioning

confidence: 99%

2,8-Diheterobicyclo[3.2.1]octane Ring Systems: Natural Occurrence, Synthesis and Properties

Flores

Dı́ez

2014

Synlett

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This account describes the developments on the synthesis and reactivity of functionalized 2,8-diheterobicyclo[3.2.1]octanes. The continued interest in the chemistry of these compounds is mainly due to their abundance in Nature, being at the core of numerous families of biologically active natural products, and also as a result of their versatile reactivity, which makes them very useful building blocks with considerable impact in modern organic synthesis. The present article is aimed toward providing a comprehensive coverage of the literature on these heterocyclic scaffolds, including our own contributions, and has been organized according to the nature of the heteroatom embedded in the 2,8-bicyclo[3.2.1]octane framework.

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“…Recently, Wang and coworkers reported two intramolecular approaches with other types of cyclopropanes: the first one involves oxycyclopropanes used in intramolecular cycloadditions to access bridged cyclopropanes (Scheme 7.5, A), [36] whereas the other made use of ketone substituted alkynyl cyclopropanes (Scheme 7.5, B). [37] In the latter case, more saturated furan derivatives could also be accessed via an alternative [4+2] annulation process if a gold catalyst was used. In 2012, Waser and co-workers reported the first use of amino-substituted cyclopropanes in the formal [3+2] cycloaddition with both aldehydes and ketones (Scheme 7.6).…”

Section: C-o Bond Formationmentioning

confidence: 99%

Synthesis of Saturated Heterocycles via Metal-Catalyzed Formal Cycloaddition Reactions That Generate a C–N or C–O Bond

Waser

2013

Topics in Heterocyclic Chemistry

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In this section, the synthesis of saturated N-and O-heterocycles via formal cycloaddition is presented. The main focus is on metal-catalyzed reactions involving C-C or C-X  bond cleavage in three-or four-membered rings. After a fast presentation of pioneering works, the important breakthroughs of the last two decades are presented. The section starts with reactions involving three-membered rings. Formal [3+2] cycloadditions of donor-acceptor-substituted cyclopropanes and methylenecyclopropanes with carbonyls and imines are important methods to access tetrahydrofuran and pyrrolidine heterocycles. Formal [3+3] cycloadditions have emerged more recently. On the other hand, reactions of epoxides and aziridines with carbon monoxide or cumulenes are now well-established method to access heterocycles. These processes have been completed more recently with cycloaddition with olefins, carbonyls and imines. The section ends with the emerging field of four-membered ring activation for cycloaddition with  systems. This is the peer reviewed version of the following article: Top. Heterocycl. Chem. 2013, 32, 225, which The discovery of classical cycloaddition reactions, such as the (hetero) DielsAlder and 1,3-dipolar cycloadditions, has contributed tremendously to a more efficient access towards both carbocycles and heterocycles. The introduction of the term cycloaddition was necessary to distinguish these new types of reactions from previously discovered processes leading to cyclic structures, such as the famous Robinson annulation. In principle, each cycloaddition can be considered as a special case of the more general annulation process, but from which point on an annulation can be called a cycloaddition has been the topic of intensive discussions for decades, and is still not settled today. In 1968, Huisgen proposed a set of rules for the definition of cycloaddition, and the two first are still largely recognized as prerequisite: Although the rule that all the atoms of the starting materials have to be included in the product is not explicitly included in the definition, this requirement is usually recognized by most organic chemists. Even if electrocyclic cyclization processes were included in the original definition of Huisgen, the term cycloaddition is mostly used today for those reactions proceeding via the formation of at least two new bonds. Nevertheless, several researchers think that the term cycloaddition should be more strictly limited to reactions involving a continuous overlap of  electrons, and consequently allowing a concerted process. In fact, in his seminal publication, Huisgen already introduced further rules, in particular rule number 3, which explicitly stated that cycloadditions should not involve the cleavage of sigma bonds: -Huisgen Rule 3: "Cycloadditions do not involve the cleavage of  bonds." Unfortunately, in the same publication, Huisgen also described several reactions proceeding via -bond cleavage as cycloaddition. To solve this definition dilemma, several researchers have used th...

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Lewis Acid Catalyzed Intramolecular [4+2] and [3+2] Cross‐Cycloaddition of Alkynylcyclopropane Ketones with Carbonyl Compounds and Imines

Cited by 100 publications

References 143 publications

Gold-Catalyzed Conversion of Highly Strained Compounds

Gold-Catalyzed Conversion of Highly Strained Compounds

2,8-Diheterobicyclo[3.2.1]octane Ring Systems: Natural Occurrence, Synthesis and Properties

Synthesis of Saturated Heterocycles via Metal-Catalyzed Formal Cycloaddition Reactions That Generate a C–N or C–O Bond

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