Nickel-Catalyzed Highly Regio- and Chemoselective Cocyclotrimerization of Propiolates with Allenes:  A Novel Route to Polysubstituted Benzene Derivatives

Shanmugasundaram, Muthian; Wu, Mengge; Cheng, Chien‐Hong

doi:10.1021/ol0169168

Cited by 68 publications

(43 citation statements)

References 16 publications

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“…It is noteworthy that the reaction proceeded satisfactorily without the need for the electron‐withdrawing CO 2 R group, which had proven crucial in other [2+2+2] cycloaddition reactions involving allenes 7a. c, 8, 10 The yields for the allene–yne–allene substrates were lower than those for the allene–ene–allene substrates due to the increased decomposition observed during the reaction.…”

Section: Resultsmentioning

confidence: 99%

Stereoselective Rhodium‐Catalysed [2+2+2] Cycloaddition of Linear Allene–Ene/Yne–Allene Substrates: Reactivity and Theoretical Mechanistic Studies

Haraburda

Torres

Parella

et al. 2014

Chemistry A European J

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Allene-ene-allene (2 and 5) and allene-yne-allene (3 and 7) N-tosyl and O-linked substrates were satisfactorily synthesised. The [2+2+2] cycloaddition reaction catalysed by the Wilkinson catalyst [RhCl(PPh3 )3 ] was evaluated. Substrates 2 and 5, which bear a double bond in the central position, gave a tricyclic structure in a reaction in which four contiguous stereogenic centres were formed as a single diastereomer. The reaction of substrates 3 and 7, which bear a triple bond in the central position, gave a tricyclic structure with a cyclohexenic ring core, again in a diastereoselective manner. All cycloadducts were formed by a regioselective reaction of the inner allene double bond and, therefore, feature an exocyclic diene motif. A Diels-Alder reaction on N-tosyl linked cycloadducts 8 and 10 allowed pentacyclic scaffolds to be diastereoselectively constructed. The reactivity of the allenes on [2+2+2] cycloaddition reactions was studied for the first time by density functional theory calculations. This mechanistic study rationalizes the order in which the unsaturations take part in the catalytic cycle, the reactivity of the two double bonds of the allene towards the [2+2+2] cycloaddition reaction, and the diastereoselectivity of the reaction.

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Section: Resultsmentioning

confidence: 99%

Stereoselective Rhodium‐Catalysed [2+2+2] Cycloaddition of Linear Allene–Ene/Yne–Allene Substrates: Reactivity and Theoretical Mechanistic Studies

Haraburda

Torres

Parella

et al. 2014

Chemistry A European J

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“…In contrast, similar transformations using allenes in place of alkenes have been reported in a limited number of examples . As examples of the cross‐cyclotrimerization of alkynes with allenes, the nickel‐catalyzed reactions of one molecule of a monosubstituted allene with two molecules of an electron‐deficient internal alkyne followed by aromatization through olefin isomerization, which affords the corresponding pentasubstituted benzenes, has been reported (Scheme a) . However, the usable alkynes are limited to electron‐deficient alkynoates, and electron‐rich alkynes cannot be employed .…”

Section: Methodsmentioning

confidence: 99%

“…As examples of the cross‐cyclotrimerization of alkynes with allenes, the nickel‐catalyzed reactions of one molecule of a monosubstituted allene with two molecules of an electron‐deficient internal alkyne followed by aromatization through olefin isomerization, which affords the corresponding pentasubstituted benzenes, has been reported (Scheme a) . However, the usable alkynes are limited to electron‐deficient alkynoates, and electron‐rich alkynes cannot be employed . Furthermore, a selective and general method for the cross‐cyclotrimerization of two molecules of an allene and one molecule of an alkyne has not been reported to date .…”

Section: Methodsmentioning

confidence: 99%

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

2016

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It has been established that ac ationic rhodium(I)/ binap complex catalyzest he cross-cyclotrimerization of two molecules of am onosubstituted allene with one molecule of af unctionalized alkyne to give 3,6-dialkylidenecyclohex-1-enes.I nc ontrast, the reactions involving di-or trisubstituted allenes and/or unfunctionalized alkynes afforded cross-dimerization products,substituted dendralenes,through b-hydrogen elimination from the corresponding rhodacycles.Transition-metal-catalyzed intermolecular cross-cyclotrimerization and cross-dimerization reactions of alkynes with alkenes are efficient and atom-economical methods for the synthesis of substituted six-membered carbocycles and dienes, respectively.[1] In contrast, similar transformations using allenes in place of alkenes have been reported in al imited number of examples.[2] As examples of the cross-cyclotrimerization of alkynes with allenes, [3][4][5] the nickel-catalyzed reactions of one molecule of am onosubstituted allene with two molecules of an electron-deficient internal alkyne followed by aromatization through olefin isomerization, which affords the corresponding pentasubstituted benzenes, has been reported (Scheme 1a).[3a] However,t he usable alkynes are limited to electron-deficient alkynoates,a nd electron-rich alkynes cannot be employed.[3a] Furthermore, as elective and general method for the cross-cyclotrimerization of two molecules of an allene and one molecule of an alkyne has not been reported to date. [5] As examples of the cross-dimerization of allenes with alkynes,t hermal reactions giving substituted dendralenes have been reported (Scheme 1b). [6][7][8] However,t he usable alkynes are limited to electron-deficient dimethyl acetylenedicarboxylate and (trifluoromethyl)acetylene.[6] Herein, we disclose the crosscyclotrimerization of two molecules of am onosubstituted allene with functionalized alkynes,a nd cross-dimerization of di-or trisubstituted allenes with both functionalized and unfunctionalized alkynes.Recently,o ur research group reported the rhodiumcatalyzed enantioselective [2+ +2+ +2] cycloaddition of tosylamide-linked 5-allenals and 5-allenones with internal alkynes. [9] In this study,w ef ound that the reaction of the tosylamide-linked 5-allenone with di-tert-butylacetylenedicarboxylate in the presence of ac ationic rhodium(I)/binap catalyst does not afford the expected [2+ +2+ +2] cycloaddition product, but instead delivers an unexpected cross-cyclotrimerization product, 3,6-dialkylidenecyclohex-1-ene derivative, in good yield (Scheme 2).Thus,w ee xamined the reaction of the monosubstituted allene 1a with di-tert-butylacetylenedicarboxylate (2a)inthe presence of the same rhodium catalyst (Table 1). Pleasingly, the cross-cyclotrimerization proceeded at room temperature to give the corresponding 3,6-dialkylidenecyclohex-1-ene 3aa,a lthough the regioisomer 4aa was generated as aminor product (entry 1). Theeffect of biaryl bis(phosphine) ligands was then examined (entries 1-5). Increasing the dihedral angle of ligands impro...

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“…Cheng et al [31][32][33] made a substantial contribution to the topic by systematically studying the intermolecular cycloaddition of allenes with alkynes and diynes (Scheme 15). In these studies, the less substituted double bonds of the allenes were found to participate in the cycloaddition.…”

Section: Intermolecular and Partially Intermolecular Cycloadditions Omentioning

confidence: 99%

“…Therefore, the allenes acted here as synthetic equivalents of monosubstituted alkynes. The first study by Cheng et al 31 was based on a completely intermolecular reaction between two molecules of alkyne and one molecule of allene under nickel catalysis, to afford polysubstituted benzene derivatives in a highly regioand chemoselective fashion (Scheme 15a). The best catalytic system found was [Ni(dppe)Br 2 ] with an excess of metallic Zn as the reductant of Ni(II) to Ni(0), which was the actual catalytic species.…”

Section: Intermolecular and Partially Intermolecular Cycloadditions Omentioning

confidence: 99%

Allenes, versatile unsaturated motifs in transition-metal-catalysed [2+2+2] cycloaddition reactions

2016

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The development of efficient reactions that enable the construction of multiple bonds and/or stereogenic centres in a single synthetic operation is of great interest for greener and step-economical syntheses of complex organic targets. Transition-metal-catalysed [2+2+2] cycloadditions excell in this regard: no fewer than three new sigma bonds and a new ring system are formed from simple unsaturated components. Allenes constitute an important subclass among these. They are more reactive than simple alkenes and generate sp(3) centres, with important stereochemical implications. In addition, further manipulation of the resulting cycloadduct through the remaining double bond is possible, increasing molecular complexity. This tutorial review highlights the value that allenes have as reagents in [2+2+2] cycloaddition and their great versatility for the development of methods to generate complex architectures.

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Nickel-Catalyzed Highly Regio- and Chemoselective Cocyclotrimerization of Propiolates with Allenes: A Novel Route to Polysubstituted Benzene Derivatives

Abstract: The Ni(dppe)Br(2)/Zn system effectively catalyzes the cocyclotrimerization of propiolates with allenes. The reaction is highly regio- and chemoselective to afford polysubstituted benzene derivatives in good to excellent yields. [reaction: see text]

Cited by 68 publications

References 16 publications

Stereoselective Rhodium‐Catalysed [2+2+2] Cycloaddition of Linear Allene–Ene/Yne–Allene Substrates: Reactivity and Theoretical Mechanistic Studies

Stereoselective Rhodium‐Catalysed [2+2+2] Cycloaddition of Linear Allene–Ene/Yne–Allene Substrates: Reactivity and Theoretical Mechanistic Studies

Rhodium‐Catalyzed Cross‐Cyclotrimerization and Dimerization of Allenes with Alkynes

Allenes, versatile unsaturated motifs in transition-metal-catalysed [2+2+2] cycloaddition reactions

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