Rhodium(I)‐Catalyzed Intermolecular [2+2+2] Cycloaddition of Allenyl Aldehydes with Alkynes and Related Cyclization

Oonishi, Yoshihiro; Saito, Akira; Sato, Yoshihiro

doi:10.1002/ajoc.201402239

Cited by 10 publications

(4 citation statements)

References 67 publications

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“…Thereafter, in 2015, Oonishi et al expanded the similar strategy where an aromatic ring and a longer C chain could be added to the tether, thus broadening the application of allenal derivatives (Scheme ). The use of 10 mol % ( R )-SEGPHOS and [Rh(COD) 2 ]ClO 4 furnished a series of enantioenriched pyran derivatives ( 60c ) from the reaction of allenal ( 60a ) and electronically biased alkyne ( 60b ) in moderate to high enantioselectivity. The reaction is proposed to proceed via a similar oxarhodacyclopentane ( 60g ) generated with the participation of the aldehyde functionality for subsequent electronic-dependent insertion with alkyne ( 60b / c ) to form 60h .…”

Section: Aa Coupling In Constructing Cyclic C-skeletonsmentioning

confidence: 99%

Intermolecular Allene–Alkyne Coupling: A Significantly Useful Synthetic Transformation

Pradhan,

Park

2024

ACS Catal.

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Because of its wide applicability in the synthesis of diverse unsaturated building blocks, allene−alkyne (AA) coupling has emerged as a powerful methodology to drive useful chemical transformations in the past two decades. Considering recent discoveries in this active research area, in this Review, we aim to support chemists in the selection of suitable methods, particularly intermolecular approaches, according to the synthesis needs. However, inherent similarities between the reactivities of π-systems create considerable obstacles while predicting selectivity in an intermolecular platform. Therefore, herein, intermolecular couplings for the chemoselective, stereoselective, and regioselective syntheses of acyclic and cyclic C-skeletons are reviewed. However, considering the lack of a well-organized review in this field, we initially provide a brief historical overview of the types of thermally induced reactions that are mostly feasible for electronically biased coupling components and are nonselective. Subsequently, emerging selective strategies are described, which include activator-controlled and neighboring functional group-assisted regio-, stereo-, and π-skeleton-divergent processes. Overall, this Review is divided into two parts. In the first part, strategies for the fabrication of acyclic C-skeletons are explained according to the reaction types. In the second part, synthetic transformations affording cyclic structures are reviewed based on the substrate class (that is, nonassisted and assisted substrates). Key reaction intermediates of each subset of coupling and factors affecting productselective discrimination of the active species with the highlight of rationale are systemically summarized. Understanding of these substrate structure-and catalyst-dependent factors provides insights into the regulation of the chemoselectivities of title AA crosscouplings and, therefore, the design of alternative catalytic routes with distinct mechanistic features.

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Section: Aa Coupling In Constructing Cyclic C-skeletonsmentioning

confidence: 99%

Intermolecular Allene–Alkyne Coupling: A Significantly Useful Synthetic Transformation

Pradhan,

Park

2024

ACS Catal.

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“…The cycloaddition also resulted in high chemo-and regio-selectivity (Scheme 15b). The authors demonstrate the advantages of allenes in comparison with analogous alkynes by performing the reaction with 1-heptyne instead of its isomeric derivative, n-butylallene (48), obtaining, in all cases, a mixture of compounds and much lower yields of the desired product.…”

Section: Intermolecular and Partially Intermolecular Cycloadditions Omentioning

confidence: 99%

“…Oonishi, Sato et al 48 later studied the same reaction, the cycloaddition of allenyl aldehydes 84 with alkynes under rhodium catalysis, broadening the scope of the allenal derivative: other tethers were used instead of the tosyl group, the carbon chain between the allene and the aldehyde moieties was elongated and an aromatic ring was added to the tether.…”

Section: Partially Intermolecular Cycloadditions Of Allenes With Alkenesmentioning

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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“…Ester Reduction. 36 DIBAL-H (1 M in DCM, 2.2 equiv) was added dropwise to a stirred solution of the ester S2 (1 equiv) in DCM (0.3 M) at −78 °C. The reaction was then stirred at that temperature for 3 h. Afterward, MeOH (5 mL) was added followed by a saturated solution of the Rochelle Salt at −78 °C.…”

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confidence: 99%

Enantioenriched α-Vinyl 1,4-Benzodiazepines and 1,4-Benzoxazepines via Enantioselective Rhodium-Catalyzed Hydrofunctionalizations of Alkynes and Allenes

et al. 2021

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Benzofused seven-membered heterocycles such as 1,4-benzo[ e ]diazepines (1,4-BZDs) and 1,4-benzo[ e ]oxazepines (1,4-BZOs) were efficiently synthesized by Rh-catalyzed hydrofunctionalization of internal alkynes and allenes in good to excellent yields. The asymmetric hydroamination of (aminomethyl)anilines gave rise to 3-vinyl-1,4-BZDs with excellent enantioselectivities. Orthogonal N -deprotection of 1,4-BZDs allowed an easy entry to an advanced pyrrolobenzodiazepine metabolite of the V 2 -receptor antagonist Lixivaptan.

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Rhodium(I)‐Catalyzed Intermolecular [2+2+2] Cycloaddition of Allenyl Aldehydes with Alkynes and Related Cyclization

Cited by 10 publications

References 67 publications

Intermolecular Allene–Alkyne Coupling: A Significantly Useful Synthetic Transformation

Intermolecular Allene–Alkyne Coupling: A Significantly Useful Synthetic Transformation

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

Enantioenriched α-Vinyl 1,4-Benzodiazepines and 1,4-Benzoxazepines via Enantioselective Rhodium-Catalyzed Hydrofunctionalizations of Alkynes and Allenes

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