137863-68-4Relevant academic research and scientific papers
Remote para-C-H Functionalization of Arenes by a D-Shaped Biphenyl Template-Based Assembly
Bag, Sukdev,Patra, Tuhin,Modak, Atanu,Deb, Arghya,Maity, Soham,Dutta, Uttam,Dey, Aniruddha,Kancherla, Rajesh,Maji, Arun,Hazra, Avijit,Bera, Milan,Maiti, Debabrata
, p. 11888 - 11891 (2015/10/05)
Site-selective C-H 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-H functionalizations stand as examples in this regard. Yet despite this significant progress, DG-assisted selective para-C-H 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-H 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-H activation. The applicability of this D-shaped biphenyl template-based strategy is demonstrated by synthesizing various complex molecules.
