Catalytic Oxidative Dehydrogenative Coupling of Cage B–H/B–H Bonds for Synthesis of Bis(<i>o</i>-carborane)s

Wu, Jin; Cao, Ke; Zhang, Caiyan; Xu, Tao-Tao; Ding, Li-Fang; Li, Bo; Yang, Junxiao

doi:10.1021/acs.orglett.9b02129

Cited by 42 publications

(22 citation statements)

References 65 publications

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“…We have previously reacted III [M = Ru, L = (p-cymene); III Ru ] following deprotonation, with [Rh(PPh 3 ) 3 Cl] under overnight reflux in tetrahydrofuran (THF) to afford IV Ru as a mixture of diastereoisomers with a total yield >50%. Repeating this reaction at room temperature, after workup involving preparative thin-layer chromatography (TLC), resulted in the isolation of a new species 1 as the main product, albeit with a modest yield (11%).…”

Section: Synthesis and Characterisation Of Compoundmentioning

confidence: 99%

“…Although deprotonation of III CoCp* with n BuLi followed by treatment with [Rh(PPh 3 ) 3 Cl] leads to the heterobimetallic IV CoCp* as a mixture of diastereoisomers [8], the same approach cannot be used with the Cp analog III CoCp because of the attack on the Cp ring by n BuLi. Accordingly, we have reverted to direct reaction between [HNMe 3 ][8- The presence of two diastereoisomers is evident from the observation of two Cp and two high-frequency C cage H resonances in the 1 H NMR spectrum, the latter assigned to the cobaltacarborane cage, and the diastereoisomeric ratio is approximately 1:1.5.…”

Section: Synthesis and Characterisation Of Compounds 2 Andmentioning

confidence: 99%

“…Recent years have witnessed a significant amount of interest in the chemistry of bis(carboranes) [1][2][3][4], particularly 1,1 -bis(ortho-carborane), formally [1-(1 -closo-1 ,2 -C 2 B 10 H 11 )-closo-1,2-C 2 B 10 H 11 ] (I), Scheme 1. This species offers a versatile scaffold for derivatisation and, amongst other studies, we have reported the single deboronation/metalation [5], double deboronation/homometalation [6] and stepwise deboronation/metalation-deboronation/heterometalation [7] of I, the latter including the use of {Rh(H)(PPh 3 ) 2 } fragments to afford homogeneous catalyst precursors [8].…”

Section: Introductionmentioning

confidence: 99%

“…Deprotonation of the endo H atom and reaction with [Rh(PPh 3 ) 3 Cl] led to isomerisation of the primed cage and the isolation of the product [8-{8 -2 -H-2 ,2 -(PPh 3 ) 2 -closo-2 ,1 ,8 -RhC 2 B 9 H 11 }-2-L-closo-2,1,8-MC 2 B 9 H 10 ] (IV) as a diastereoisomeric mixture [8]. Compounds of type IV were found to be active catalyst precursors for alkene isomerisation and the hydrosilylation of acetophenone.…”

Section: Introductionmentioning

confidence: 99%

“…Seeking to expand the scope of this chemistry, we have now investigated the reactions of III [M = Ru, L = (p-cymene); M = Co, L = Cp] with [Rh(PPh 3 ) 3 Cl] under different conditions and here present the results. Whilst these new reactions also afford compounds of type IV as minor co-products, the major species produced are unique heterometalated derivatives of bis(carborane), each isolated in only one of two possible diastereoisomeric forms.…”

Section: Introductionmentioning

confidence: 99%

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Exopolyhedral Ligand Orientation Controls Diastereoisomer in Mixed-Metal Bis(Carboranes)

2020

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Heterobimetallic derivatives of a bis(carborane), [µ 7,8 -(1 ,3 −3 -Cl-3 -PPh 3 -closo-3 ,1 ,2 -RhC 2 B 9 H 10 )-2-(p-cymene)-closo-2,1,8-RuC 2 B 9 H 10 ] (1) and [µ 7,8 -(1 ,3 −3 -Cl-3 -PPh 3 -closo-3 ,1 ,2 -RhC 2 B 9 H 10 )-2-Cp-closo-2,1,8-CoC 2 B 9 H 10 ] (2) have been synthesised and characterised, including crystallographic studies. A minor co-product during the synthesis of compound 2 is the new species [8-{8 -2 -H-2 ,2 -(PPh 3 ) 2 -closo-2 ,1 ,8 -RhC 2 B 9 H 10 }-2-Cp-closo-2,1,8-CoC 2 B 9 H 10 ] (3), isolated as a mixture of diastereoisomers. Although, in principle, compounds 1 and 2 could also exist as two diastereoisomers, only one (the same in both cases) is formed. It is suggested that the preferred exopolyhedral ligand orientation in the rhodacarboranes in the non-observed diastereoisomers would lead to unacceptable steric crowding between the PPh 3 ligand and either the p-cymene (compound 1) or Cp (compound 2) ligand of the ruthenacarborane or cobaltacarborane, respectively.

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Section: Synthesis and Characterisation Of Compoundmentioning

confidence: 99%

Section: Synthesis and Characterisation Of Compounds 2 Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exopolyhedral Ligand Orientation Controls Diastereoisomer in Mixed-Metal Bis(Carboranes)

2020

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Selective Functionalization of BH Bond of o ‐Carboranes

Cao¹,

Zhang²,

Wu³

et al. 2022

Handbook of CH-Functionalization

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Icosahedral carboranes are a class of carbon–boron molecular clusters with three‐dimensional aromaticity, which have growing applications in functional materials, boron neutron capture therapy agents, organometallic, and coordination chemistry. To further expand the application of o ‐carboranes, the functionalization of o ‐carboranes with diverse groups and controllable regioselectivity has been a challenging subject as the 10 BH bonds are not fully equal and have a slight difference in reactivity. In the past six years, transition metal‐catalyzed BH activation has been proved to be a powerful tool to accomplish the regioselective functionalization of o ‐carboranes and achieved much advancement in this field. This article summarizes recent advances around BH activation.

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Recent Advance in Transition Metal‐Catalyzed Carboxylic Acid Guided B−H Functionalization of Carboranes

et al. 2022

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Carboranes, a three-dimensional class of carbon-boron molecular clusters with remarkable electronic, physical, chemical characteristics, have proved as useful building blocks in boron neutron capture therapy agents, supramolecular design, optoelectronics, nanomaterials and organometallic/coordination chemistry. Thus, various organic modifications of the BÀ H and CÀ H functionalities in carboranes have been developed. These methods with great success utilize directing groups, such as carboxylic acids, to achieve a selective BÀ H functionalization of carboranes. The carboxyl group can be easily introduced to carboranes and then be removed after reactions. On the other hand, assisted by the carboxyl group a highly regioselective electrophilic attack at the electron-rich positions B(4) and B(5) of the cage generates five-membered metallacyclic intermediates, which then undergo further transformation. In this review, we show that transition metal-catalyzed decarboxylation cross coupling reactions offer an opportunity for the selective and direct BÀ H activation of carboranes. 1. Introduction 2. Formation of BÀ C(sp 2 ) Bonds 3. Formation of BÀ C(sp) Bonds 4. Formation of BÀ C(sp 3 ) Bonds 5. Formation of BÀ N Bonds 6. Formation of BÀ O Bonds 7. Formation of BÀ X Bonds 8. Formation of BÀ N Bonds and BÀ C(sp 2 ) Bonds 9. Formation of CÀ N Bonds 10. Conclusions and Outlooks

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Catalytic Oxidative Dehydrogenative Coupling of Cage B–H/B–H Bonds for Synthesis of Bis(o-carborane)s

Cited by 42 publications

References 65 publications

Exopolyhedral Ligand Orientation Controls Diastereoisomer in Mixed-Metal Bis(Carboranes)

Exopolyhedral Ligand Orientation Controls Diastereoisomer in Mixed-Metal Bis(Carboranes)

Selective Functionalization of BH Bond of o ‐Carboranes

Recent Advance in Transition Metal‐Catalyzed Carboxylic Acid Guided B−H Functionalization of Carboranes

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