- Inter- and intra-molecular C-H borylation for the formation of PAHs containing triarylborane and indole units
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Inter-/intra-molecular electrophilic C-H borylation of C4-substituted indoles enables the formation of fused polycyclic aromatic structures containing triarylborane and N-heterocyclic units. These compounds are B-(C)n-N isosteres of carbocyclic PAHs that do not contain B-N bonds and comparison of one pair of BN/CC isosteres reveals that different resonance structures dominate. These compounds are highly sensitive to protodeboronation, of both the chloroborane intermediates and the mesityl protected products, which results in low isolated yields of the latter. Protodeboronation can be utilised productively for a C-H directed, C-H electrophilic borylation to make a previously unknown pinacol boronate ester by selective protodeboronation of the chloroborane intermediate. Intermolecular and double intramolecular electrophilic C-H borylation of a C4-substituted indole leads to a more highly fused structure containing two boracycles which represents a B-(C)n-N analogue of the unknown carbon isostere indeno[1,7ab]perylene.
- Escande,Crossley,Cid,Cade,Vitorica-Yrezabal,Ingleson
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supporting information
p. 17160 - 17167
(2016/11/13)
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- Direct C(sp2)-C(sp3) cross-coupling of diaryl zinc reagents with benzylic, primary, secondary, and tertiary alkyl halides
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The direct C(sp2)-C(sp3) cross-coupling of diaryl zinc reagents with benzylic, primary, secondary, and tertiary alkyl halides proceeded in the absence of coordinating ethereal solvents at ambient temperature without the addition of a catalyst. The C(sp2)-C(sp3) cross-coupling showed excellent functional-group tolerance, and products were isolated in high yields, generally without the requirement for purification by chromatography. This process represents an expedient, operationally simple method for the construction of new C(sp2)-C(sp3) bonds. Zinc and you'll miss it. Direct C(sp2)-C(sp3) cross-coupling of diaryl zinc reagents with alkyl halides proceeded rapidly at ambient temperature without a coordinating ethereal solvent or an added catalyst (see scheme). This versatile, operationally simple approach to C(sp2)-C(sp3) bond formation enables the expedient construction of a diverse array of carbon-based structural motifs.
- Dunsford, Jay J.,Clark, Ewan R.,Ingleson, Michael J.
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supporting information
p. 5688 - 5692
(2015/05/19)
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- Direct C-C bond construction from arylzinc reagents and aryl halides without external catalysts
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Direct cross-coupling between an arylzinc reagent and an aryl halide was accomplished without any external catalyst, enabling efficient and selective formation of the corresponding biaryl compound with broad functional group compatibility. Direct cross-coupling between a diarylzinc compound and an aryl iodide was accomplished without using any external catalyst. The reaction is efficient and selective, enabling formation of the corresponding biaryl compounds with broad functional group compatibility. The reaction is proposed to proceed by a thermally initiated single electron transfer (SET) route. Copyright
- Minami, Hiroki,Wang, Xuan,Wang, Chao,Uchiyama, Masanobu
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supporting information
p. 7891 - 7894
(2014/01/06)
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- Dimesitylzinc: A strictly 2-coordinate, homoleptic diarylzinc compound
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Unprecedented aryl transfer from boron to zinc generated Zn(mes)2, the structure of which revealed a linear, two coordinate metal in which there is no stabilisation by interor intramolecular interactions.
- Cole, Sarah C.,Coles, Martyn P.,Hitchcock, Peter B.
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p. 3663 - 3664
(2007/10/03)
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