para-Selective Arylation of Arenes: A Direct Route to Biaryls by Norbornene Relay Palladation |
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Authors: | Dr. Uttam Dutta Sandip Porey Sandeep Pimparkar Astam Mandal Jagrit Grover Adithyaraj Koodan Dr. Debabrata Maiti |
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Affiliation: | 1. Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076 India;2. Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400 076 India These authors contributed equally to this work. |
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Abstract: | Biaryl compounds are extremely important structural motifs in natural products, biologically active components and pharmaceuticals. Selective synthesis of biaryls by distinguishing the subtle reactivity difference of distal arene C−H bonds are significantly challenging. Herein, we describe para-selective C−H arylation, which is acheived by a unique combination of a meta-directing group and norbornene as a transient mediator. Upon direct meta-C−H palladation, one-bond relay palladation occurs in presence of norbornene and subsequently para-C−H arylation is achieved for sulfonates, phosphonates and phenols bearing 2,6-disubstitution patterns. The protocol is amenable to electron-deficient aryl iodides. Multisubstituted arenes and phenols are obtained by postsynthetic modification of the products. The protocol allows the synthesis of hexa-substituted benzene by sequential selective distal C−H functionalization. |
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Keywords: | arylation Catellani reaction C−H activation palladation relay reactions |
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