6304-24-1Relevant articles and documents
Palladium-Catalyzed Direct Arylation of Alkylpyridine via Activated N-Methylpyridinium Salts
Chen, Xue,Li, Wen-Jing,Li, Shun,Tang, Juan,Du, Xi,Zheng, Xue-Li,Yuan, Mao-Lin,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua
, p. 622 - 632 (2019/12/30)
An efficient Pd-catalyzed arylation of alkylpyridine based on the pyridinium activation strategy has been developed for synthesis of mixed aryl alkylpyridines. It was found that (1) the N-methyl group in the pyridinium salts acted as a transient activator and could be automatically departed after the reaction, (2) CuBr was an indispensable additive for achieving the C6-selective arylation, (3) the α-branched alkyl chain on the alkylpyridine greatly increased the yield of the product. Deuterium labelling experiment revealed that in the case of the α-branched alkylpyridine, the presence of CuBr completely inhibited the H/D exchange at the benzylic position and thus enabled the selective arylation at the C6 position. This protocol demonstrates a broad substrate scope, and with respect to both the aryl iodides and the α-branched alkylpyridine, the desired mixed aryl alkylpyridines were obtained in generally good to excellent yields.
Enantioselective Alkylation of 2-Alkylpyridines Controlled by Organolithium Aggregation
Gladfelder, Joshua J.,Ghosh, Santanu,Podunavac, Ma?a,Cook, Andrew W.,Ma, Yun,Woltornist, Ryan A.,Keresztes, Ivan,Hayton, Trevor W.,Collum, David B.,Zakarian, Armen
supporting information, p. 15024 - 15028 (2019/10/22)
Direct enantioselective α-alkylation of 2-alkylpyridines provides access to chiral pyridines via an operationally simple protocol that obviates the need for prefunctionalization or preactivation of the substrate. The alkylation is accomplished using chiral lithium amides as noncovalent stereodirecting auxiliaries. Crystallographic and solution NMR studies provide insight into the structure of well-defined chiral aggregates in which a lithium amide reagent directs asymmetric alkylation.
Photocatalyzed Site-Selective C(sp3)-H Functionalization of Alkylpyridines at Non-Benzylic Positions
Fukuyama, Takahide,Nishikawa, Tomohiro,Yamada, Keiichi,Ravelli, Davide,Fagnoni, Maurizio,Ryu, Ilhyong
supporting information, p. 6436 - 6439 (2017/12/08)
Tetrabutylammonium decatungstate (TBADT)-photocatalyzed C-H functionalization of alkylpyridines was investigated. Unlike alkylbenzene counterparts, alkylation of α-C-H bonds did not proceed for the reaction of 2- and 4-alkylpyridines and reluctantly proceeded for 3-alkylpyridines, which allow site-selective C(sp3)-H functionalization at nonbenzylic positions. The observed nonbenzylic site selectivities are rationalized by the polar inductive effects of pyridyl groups in the SH2 transition states. Consecutive γ-functionalization and α-bromofunctionalization were successfully carried out in selected cases.
