Three‐Component [2+2+2] Cycloaddition of Carboryne, Unactivated Alkene, and Alkyne via Zirconacyclopentane Mediated by Nickel: One‐Pot Synthesis of Dihydrobenzocarboranes

Ren, Shikuo; Qiu, Zaozao; Xie, Zuowei

doi:10.1002/anie.201106212

Cited by 29 publications

(18 citation statements)

References 48 publications

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“…35 Symmetrical alkynes give the single products in very good isolated yields. The regioselectivity in the reaction of unsymmetrical alkynes is dependent upon both the polarity of alkynes and relative bulkiness of two substituents.…”

Section: Reaction With Alkenesmentioning

confidence: 99%

Recent advances in transition metal-mediated functionalization of o-carboranes

Qiu

2015

Tetrahedron Letters

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a b s t r a c tIcosahedral carboranes constitute a class of structurally unique molecules with exceptionally thermal and chemical stabilities, which limits the derivatization of these clusters. In view of the spectacular role of transition metals in synthetic chemistry, novel o-carborane functionalization methods for both cage carbon and boron vertices have been developed by using transition metal-promoted reactions. These methods offer a series of exceptionally efficient synthetic routes to a wide range of functionalized carboranes from readily available starting materials. An overview of recent advances in this field is presented in this digest.

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Section: Reaction With Alkenesmentioning

confidence: 99%

Recent advances in transition metal-mediated functionalization of o-carboranes

Qiu

2015

Tetrahedron Letters

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“…此锆杂五元环化合物并不能进一步与炔烃反应, 考虑到镍杂五元环化合物更高的反应活性, 4 在 NiCl 2 (PMe 3 ) 2 存在下可以与另一分子炔烃反应(Scheme 2) [23] : 2009 年, 谢作伟课题组 [24] [25] , 插入反应的区域选择性由烯烃上取代基的电性决定(Scheme 5): 给电子烷基位于金属 β 位(8a)而吸电子芳基位于金属 α 位(8b). 同样 8 与炔烃在 NiCl 2 存在下进一步反应, 能以最高 88%收率合成二氢苯并碳硼烷 9 [26] 二氢富烯并碳硼烷化合物 11 (Scheme 7) [27] . 在对该特殊 [2＋2＋1]环加成反应的机理研究中, 林振阳小组和谢作伟小组 [28]…”

Section: 碳碳-取代碳硼烷衍生物的合成unclassified

Recent Advances in Transition Metal-Promoted Multicomponent Cascade Reactions for Controlled Synthesis of Complex Carborane Derivatives

Zhang¹,

Qiu²,

Xie³

2020

Chin. J. Org. Chem.

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Carboranes are a class of carbon-boron molecular clusters with exceptional thermal and chemical stabilities. They are finding a variety of applications in medicine, materials, and coordination/organometallic chemistry as functional building blocks. To this end, the selective functionalization of carboranes has received growing research interests. Transition metal-promoted multicomponent cascade reactions are particularly attractive since they have the advantages of step-and atomeconomy for the construction of complex products from readily available starting materials by simple operations. The recent advances in transition metal-promoted multicomponent cascade reactions for selective functionalization of carboranes are summarized in this focus review. The related reaction mechanisms and challenges in this research area are also discussed.

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“…According to previous reports [17], alkene insertion into the Ni-C bond is preferred over alkyne insertion when the Ni-carboranyl compound undergoes cycloaddition with alkene and alkyne. Also, in the presence of NiCl 2 (PMe 3 ) 2 , o-carboranylzirconacycle R1 would interact with alkene R2 and the catalyst to form a nickelacyclopentane intermediate M1 by transmetallation [16,20,26], then M1 complexes with alkyne to form a new compound INT1 (Scheme 2). However, affected by variable orientation of n Bu group in intermediate M1 and subsequent B-H activation sites of o-carborane, the reaction shown in Scheme 1 led to a diastereoselective mixture of P1a and P1b (dr ≈ 1:1) [25].…”

Section: Formation Mechanism Of Dihydrofulvenocarborane Intermediate mentioning

confidence: 99%

“…Due to its unique electronic properties and geometrical structure, the icosahedral o-carborane possesses unusual reactivity and can be activated by transition metal through C-H or B-H activation, to form a wide variety of o-carborane derivatives [8][9][10][11][12][13]. Remarkable achievements, in terms of substrate expansion, optimization of experimental conditions, and product yield enhancement, have been made in C-H activation and functionalization of o-carborane in recent years [8,9,[14][15][16]. Based on computational simulations, some scholars have even presented reasonable explanations for reaction mechanisms and regioselectivity of C-H activation in o-carborane [17][18][19][20][21][22][23], which has also promoted the rapid development of this area.…”

Section: Introductionmentioning

confidence: 99%

Computational Investigation of Nickel-Mediated B–H Activation and Regioselective Cage B–C(sp2) Coupling of o-Carborane

Liu

Cheng

et al. 2019

Catalysts

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Density functional theory (DFT) methods including LC-ωPBE, CAM-B3LYP, B3LYP, and B3LYP-D3, combined with double Zeta all-electron DZVP basis set, have been employed to conduct computational investigations on nickel-mediated reaction of o-carboranylzirconacycle, n-hexene, and 2-bromophenyltrimethylsilylacetylene in toluene solution. A multistep mechanism leading to the C,C,B-substituted carborane-fused tricyclics, including (1) sequential insertion of alkene and alkyne into Ni-C bonds; (2) double 1,2-migration of the TMS group; (3) B-H activation assisted by Cs 2 CO 3 additive; and (4) reduction cage B-C (sp 2 ) coupling, was proposed. Among these steps, the B-H activation of o-carborane was located as rate-determining step (RDS). With assistance of Cs 2 CO 3 additive (replaced by K 2 CO 3 in simulation), the RDS free-energy barrier at PCM-LC-ωPBE/DZVP level was calculated to be 23.1-23.9 kcal·mol −1 , transferring to a half-life of 3.9-15.1 h at 298 K. The predicted half-life coincides well with 80% experimental yields of C,C,B-substituted carborane-fused tricyclics after 12 h. Kinetic data obtained by employing LC-ωPBE method also reproduced the experimental diastereoselective ratio well. Various B-H activation pathways with and without Cs 2 CO 3 additive were taken into consideration, which illustrates Cs 2 CO 3 as an essential guarantee for smooth occurrence of this reaction at room temperature.Catalysts 2019, 9, 548 2 of 16 and has always been a focus in the field [10][11][12][13]. In recent decades, people have made significant achievements in nickel-catalyzed selective activation of B-H bonds in o-carborane, generally by introducing a directing group in substrates. For example, in 2010, Qiu and Xie had realized the palladium/nickel co-mediated [2+2+2] cyclization of 1-lithium-2-methyl-3-iodo-o-carborane with twice equivalent of alkynes, and prepared 1-C-3-B-substituted o-carborane derivative successfully [24]. This reaction has not only excellent yield but also good regioselectivity. In 2014, Xie's group had achieved three-component cyclization of o-carborane with olefin and halogenated phenyl alkyne through zirconium/nickel co-mediated coupling, and prepared a series of novel C,C,B-substituted carborane-fused tricyclics successfully (Scheme 1) [25]. This work represents the first example of cage B-C(sp 2 ) coupling by direct B-H activation of o-carborane, which is of great significance for the regioselective B-H activation and functionalization of o-carborane derivatives. What particularly worth mentioning is, the reaction can process at room temperature and corresponding C,C,B-substituted carborane-fused tricyclics (P1) can be obtained with a yield up to 80% by adding Cs 2 CO 3 additive (Entry 2 in Scheme 1). Catalysts 2019, 9, x FOR PEER REVIEW 2 of 16 achievements in nickel-catalyzed selective activation of B-H bonds in o-carborane, generally by introducing a directing group in substrates. For example, in 2010, Qiu and Xie had realized the palladium/nickel co-mediated [2+2+2] cyclization of 1-lithium-2-...

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Three‐Component [2+2+2] Cycloaddition of Carboryne, Unactivated Alkene, and Alkyne via Zirconacyclopentane Mediated by Nickel: One‐Pot Synthesis of Dihydrobenzocarboranes

Cited by 29 publications

References 48 publications

Recent advances in transition metal-mediated functionalization of o-carboranes

Recent advances in transition metal-mediated functionalization of o-carboranes

Recent Advances in Transition Metal-Promoted Multicomponent Cascade Reactions for Controlled Synthesis of Complex Carborane Derivatives

Computational Investigation of Nickel-Mediated B–H Activation and Regioselective Cage B–C(sp2) Coupling of o-Carborane

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