Synthese von Heterocyclen durch CC‐Knüpfung. I. Edelmetall‐katalysierte Cyclisierung von Acrylsäure‐diallylamid

Schmitz, Ernst; Urban, Rainer; Heuck, Uwe; Zimmermann, G.; Gründemann, E.

doi:10.1002/prac.19763180203

Cited by 29 publications

(9 citation statements)

References 3 publications

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“…The palladium chloride mediated cycloisomerization of 1,6-dienes 26,27,29 proceeds under the same conditions as the reaction utilizing rhodium trichloride, however, in the case of palladium a different regiochemical outcome is observed. Obtention of the internal olefin is most likely due to in situ isomerization of the initially derived alkylidenecyclopentane (Equations 17 and 18).…”

Section: B Palladium Based Catalyst Systemsmentioning

confidence: 80%

“…For the case of rhodium, both rhodium trichloride 26 and Wilkinson's catalyst 27,28 have proven to be effective catalysts. Thus, 1,6-dienes 42 and 44 cycloisomerize in good yield to provide methylene cyclopentanes (Equations 15 and 16).…”

Section: Alkenes As Enophiles a Rhodium Based Catalyst Systemsmentioning

confidence: 99%

“…34 The geometry of the ene partner dictates the relative stereochemistry at the newly formed bond as evidenced by the cyclization of the cis-ene partner 66 and the corresponding trans-isomer 64 (Equations 25 and 24 respectively). 35 The formation of five-and six-membered rings proceeds with equal facility as evidenced by the efficient cyclization of 68 to the cyclohexyl derivative 69 (Equation 26). 36 These iron mediated reactions presumably involve a catalytic cycle mechanistically analogous to that of the Pd(II)-Pd(IV) mediated enyne cycloisomerization (Scheme 2).…”

Section: Iron Based Catalyst Systemsmentioning

confidence: 99%

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Transition Metal Catalyzed Cycloisomerizations

Trost¹,

Krische²

1998

Synlett

446

153

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IntroductionThe increasing need for environmentally responsible means of preparing the diverse range of chemical products demanded by society drives the quest for synthetic efficiency. Thus, in order to minimize the usage of raw materials and waste production, a chemical reaction should proceed with high levels of atom economy 1 and selectivity (chemo-, regio-, diastereo-, and enantioselectivity). Toward this ideal, the use of homogeneous transition metal catalysts in conjunction with chiral ligand fields has garnered much success.This review will focus upon the subset of transition metal catalyzed carbon-carbon bond forming reactions that occur intramolecularly and proceed with quantitative atom economy, i.e. cycloisomerization reactions. Related metal catalyzed cycloadditions, such as the metal catalyzed Diels-Alder and carbonylations like the Pauson-Khand reactions, are not discussed. Since natural product synthesis is often the arena in which the scope and limitation of methodologies are assessed, emphasis will be placed on the transformation of substrates en route to complex organic molecules. Survey of Reaction Types A. Ene-Type CyclizationsThe ene reaction 2a-d as defined by Alder 3 is an indirect substitutive addition reaction of an olefin containing an allylic hydrogen (the "ene" partner) with a molecule containing a π-bond (the "enophile").Abstract: Transformations that occur with complete atom economy minimize utilization of raw material and produce no waste and thus represent an upper limit of synthetic efficiency. Transition metal catalyzed cycloisomerizations represent a major class of atom economical reactions. Examples of the myriad of reaction types involving transition metal catalyses that comprise this class of chemical transformations are presented herein.

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Section: B Palladium Based Catalyst Systemsmentioning

confidence: 80%

Section: Alkenes As Enophiles a Rhodium Based Catalyst Systemsmentioning

confidence: 99%

Section: Iron Based Catalyst Systemsmentioning

confidence: 99%

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Transition Metal Catalyzed Cycloisomerizations

Trost¹,

Krische²

1998

Synlett

446

153

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“…A few years later the same cycloisomerisation catalysed by cationic Ni-phosphine complexes was studied extensively by Bogdanovic, 9 and Schmitz reported on the Pd-catalysed and the Rh-catalysed cycloisomerisation of N,N-diallyl acrylamide which gave a host of products (the Rh-catalysed process being marginally more selective). 10 Interestingly, the acrylamide moiety participated extensively in the Pd-catalysed process (giving lactams) whereas the opposite outcome was apparent with Rh (giving pyrollidine isomers). When the complexity of substrate (and thus product range) was reduced from a triene to a 1,6diene, in the form of N,N-diallyl amides (e.g.…”

Section: Origins and Evolution Of The Reaction Class 21 16-dienesmentioning

confidence: 99%

Mechanistic aspects of transition metal catalysed 1,6-diene and 1,6-enyne cycloisomerisation reactions

Lloyd‐Jones

2002

Org. Biomol. Chem.

413

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“…For example, both rhodium trichloride [22,23] and Wilkinson's catalyst [24,25] promote this reaction efficiently to give methylenecyclopentane 26 (Scheme 7.12). In the latter case, the active catalyst species is believed to be [Rh Rhodium(I) complexes have also been shown to promote metallo-ene type reactions efficiently (Scheme 7.14) [26].…”

Section: Cycloisomerization Of Dienesmentioning

confidence: 99%

Rhodium(I)‐Catalyzed Cycloisomerization and Cyclotrimerization Reactions

Fujiwara

Ojima

2005

Modern Rhodium‐Catalyzed Organic Reactions

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IntroductionHighly efficient catalytic processes for the synthesis of natural and unnatural compounds of medicinal interest or functional materials play a central role in modern organic synthesis. The transformation of simple starting materials into monocyclic, bicyclic, and polycyclic scaffolds using transition metal-catalyzed cyclization reactions is one of the most powerful approaches to such methodology. Among the transition metal catalysts used in these reactions, rhodium complexes are particularly important because of their high efficiency and broad functional group tolerance.The carbocyclizations of enynes, ynals, dienes, and diynes, as well as enediynes, dienynes, diynals, and triynes, are extremely important and useful reactions for the syntheses of a variety of carbocyclic compounds. Cascade carbocyclization is a powerful method, providing a rapid access to polycyclic skeletons in a single step. The term "carbocyclization" has been used to describe an annulation process involving carboncarbon bond formation via carbometallation, which distinguishes it from radical cyclization as well as from thermal and photochemical cycloadditions. When the carbocyclization process incorporates carbon monoxide, this process is categorized as carbonylative carbocyclization, which provides efficient routes to cyclic and fused cyclic ketones. Excellent reviews have been published on transition metal-mediated carbocyclizations [1] and cycloadditions [2] covering the major advances in this field up to 1996. Metalassisted cycloaddition reactions [3] and their applications to polysubstituted benzene derivatives [4] as well as to medium-sized ring syntheses [5], have also been reviewed. A review on the reactions involving hydrosilane, carbon monoxide, and unsaturated substrates promoted by transition-metal catalysts was published in 1996 [6]. This chapter describes recent advances in the rhodium-catalyzed carbocyclization processes, including various cascade-and carbonylative carbocyclizations. Carbocyclization 7.2.1Cycloisomerization of Enynes 7.2.1.1 Cycloisomerization Transition metal-catalyzed intramolecular cycloisomerization of enynes represents one of the most useful carbocyclization reactions; specifically, the rhodium-catalyzed cycloisomerization of 1,6-enynes that provide 1,3-and 1,4-dienes with high degrees of regioand stereoselectivity has been extensively studied. Cyclization of 1,6-enyne 1 catalyzed by RhCl(PPh 3 ) 3 gives 1-exo-methylene-2-cyclohexene 2 regioselectively, via a 6-exo-trig mode in 83% yield (Eq. 1) [7]. Substitution in the alkene moiety suppresses the cyclization significantly, while substitution of the terminal triple bond shuts down the reaction. 7 Rhodium(I)-Catalyzed Cycloisomerization and Cyclotrimerization Reactions 130 Scheme 7.1 Silylcarbocyclization (SiCaC and CO-SiCaC)In the first rhodium-catalyzed carbonylative silylcarbocyclization (CO-SiCaC), which was reported in 1992 [12,13], silylcyclopentenone 9 was isolated as a minor product in the silylformylation of 1-hexyne 8 (Scheme 7.4). Un...

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Synthese von Heterocyclen durch CC‐Knüpfung. I. Edelmetall‐katalysierte Cyclisierung von Acrylsäure‐diallylamid

Cited by 29 publications

References 3 publications

Transition Metal Catalyzed Cycloisomerizations

Transition Metal Catalyzed Cycloisomerizations

Mechanistic aspects of transition metal catalysed 1,6-diene and 1,6-enyne cycloisomerisation reactions

Rhodium(I)‐Catalyzed Cycloisomerization and Cyclotrimerization Reactions

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