104375-73-7Relevant academic research and scientific papers
Heterocyclization involving benzylic C(sp3)-H functionalization enabled by visible light photoredox catalysis
Pandey, Ganesh,Laha, Ramkrishna,Mondal, Pradip Kumar
supporting information, p. 9689 - 9692 (2019/08/15)
A general and efficient method for heterocyclization involving benzylic C(sp3)-H functionalization enabled by visible light photoredox catalysis to access a wide range of structurally diverse oxygen as well as nitrogen heterocycles up to a gram scale is reported. The potential application of this new methodology is demonstrated by the total synthesis of (-)-codonopsinine and (+)-centrolobine. Herein it is proposed that selectfluor, unlike a fluorinating reagent, acts as an oxidative quencher and a hydrogen radical acceptor.
C-H bond functionalization via hydride transfer: Formation of α-arylated piperidines and 1,2,3,4-tetrahydroisoquinolines via stereoselective intramolecular amination of benzylic C-H bonds
Vadola, Paul A.,Carrera, Ignacio,Sames, Dalibor
experimental part, p. 6689 - 6702 (2012/10/18)
We here report a study of the intramolecular amination of sp3 C-H bonds via the hydride transfer cyclization of N-tosylimines (HT-amination). In this transformation, 5-aryl aldehydes are subjected to N-toluenesulfonamide in the presence of BF3?OEt2 to effect imine formation and HT-cyclization, leading to 2-arylpiperidines and 3-aryl-1,2,3,4- tetrahydroisoquinolines in a one-pot procedure. We examined the reactivity of a range of aldehyde substrates as a function of their conformational flexibility. Substrates of higher conformational rigidity were more reactive, giving higher yields of the desired products. However, a single substituent on the alkyl chain linking the N-tosylimine and the benzylic sp3 C-H bonds was sufficient for HT-cyclization to occur. In addition, an examination of various arenes revealed that the electronic character of the hydridic C-H bonds dramatically affects the efficiency of the reaction. We also found that this transformation is highly stereoselective; 2-substituted aldehydes yield cis-2,5-disubstituted piperidines, while 3-substituted aldehydes afford trans-2,4-disubstituted piperidines. The stereoselectivity is a consequence of thermodynamic control. The pseudoallylic strain between the arene and tosyl group on the piperidine ring is proposed to rationalize the greater stability of the isomer with the aryl ring in the axial position. This preferential placement of the arene is proposed to affect the observed stereoselectivity.
Synthesis of Five- and Six-Membered Nitrogen Heterocycles via a Palladium(II)-Catalyzed Cyclization of Unsaturated Amides
Tamaru, Yoshinao,Hojo, Makoto,Kawamura, Shin-ichi,Yoshida, Zen-ichi
, p. 4089 - 4090 (2007/10/02)
Palladium(II)-catalyzed arylation of N-4-pentenyl-p-toluenesulfonamides 2 with ArSn(n-Bu)3 under oxidative conditions (CuCl2 in ether) provides either 2-arylpiperidines 5 or N-(chloro-5-arylpentyl)-p-toluenesulfonamides 6 depending on the kind of arylatin
