Remote para-C鈥揌 Functionalization of Arenes by a D-Shaped Biphenyl Template-Based Assembly

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• 作者：Sukdev Bag ; Tuhin Patra ; Atanu Modak ; Arghya Deb ; Soham Maity ; Uttam Dutta ; Aniruddha Dey ; Rajesh Kancherla ; Arun Maji ; Avijit Hazra ; Milan Bera ; Debabrata Maiti
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 23, 2015
• 年：2015
• 卷：137
• 期：37
• 页码：11888-11891
• 全文大小：505K
• ISSN：1520-5126

文摘

Site-selective C鈥揌 functionalization has emerged as an efficient tool in simplifying the synthesis of complex molecules. Most often, directing group (DG)-assisted metallacycle formation serves as an efficient strategy to ensure promising regioselectivity. A wide variety of ortho- and meta-C鈥揌 functionalizations stand as examples in this regard. Yet despite this significant progress, DG-assisted selective para-C鈥揌 functionalization in arenes has remained unexplored, mainly because it involves the formation of a geometrically constrained metallacyclic transition state. Here we report an easily recyclable, novel Si-containing biphenyl-based template that directs efficient functionalization of the distal p-C鈥揌 bond of toluene by forming a D-shaped assembly. This DG allows the required flexibility to support the formation of an oversized pre-transition state. By overcoming electronic and steric bias, para-olefination and acetoxylation were successfully performed while undermining o- and m-C鈥揌 activation. The applicability of this D-shaped biphenyl template-based strategy is demonstrated by synthesizing various complex molecules.