1535484-01-5Relevant academic research and scientific papers
Hydrogen-bond-assisted controlled C-H functionalization via adaptive recognition of a purine directing group
Kim, Hyun Jin,Ajitha, Manjaly J.,Lee, Yongjae,Ryu, Jaeyune,Kim, Jin,Lee, Yunho,Jung, Yousung,Chang, Sukbok
supporting information, p. 1132 - 1140 (2014/02/14)
We have developed the Rh-catalyzed selective C-H functionalization of 6-arylpurines, in which the purine moiety directs the C-H bond activation of the aryl pendant. While the first C-H amination proceeds via the N1-chelation assistance, the subsequent second C-H bond activation takes advantage of an intramolecular hydrogen-bonding interaction between the initially formed amino group and one nitrogen atom, either N1 or N7, of the purinyl part. Isolation of a rhodacycle intermediate and the substrate variation studies suggest that N1 is the main active site for the C-H functionalization of both the first and second amination in 6-arylpurines, while N7 plays an essential role in controlling the degree of functionalization serving as an intramolecular hydrogen-bonding site in the second amination process. This pseudo-Curtin-Hammett situation was supported by density functional calculations, which suggest that the intramolecular hydrogen-bonding capability helps second amination by reducing the steric repulsion between the first installed ArNH and the directing group.
