4812-65-1Relevant academic research and scientific papers
Palladium-Catalyzed C(sp3)?H Arylation of Primary Amines Using a Catalytic Alkyl Acetal to Form a Transient Directing Group
St John-Campbell, Sahra,Ou, Alex K.,Bull, James A.
supporting information, p. 17838 - 17843 (2018/11/23)
C?H Functionalization of amines is a prominent challenge due to the strong complexation of amines to transition metal catalysts, and therefore typically requires derivatization at nitrogen with a directing group. Transient directing groups (TDGs) permit C?H functionalization in a single operation, without needing these additional steps for directing group installation and removal. Here we report a palladium catalyzed γ-C?H arylation of amines using catalytic amounts of alkyl acetals as transient activators (e.g. commercially available (2,2-dimethoxyethoxy)benzene). This simple additive enables arylation of amines with a wide range of aryl iodides. Key structural features of the novel TDG are examined, demonstrating an important role for the masked carbonyl and ether functionalities. Detailed kinetic (RPKA) and mechanistic investigations determine the order in all reagents, and identify cyclopalladation as the turnover limiting step. Finally, the discovery of an unprecedented off-cycle free-amine directed ?-cyclopalladation of the arylation product is reported.
Catalytic C(sp3)?H Arylation of Free Primary Amines with an exo Directing Group Generated In Situ
Xu, Yan,Young, Michael C.,Wang, Chengpeng,Magness, David M.,Dong, Guangbin
supporting information, p. 9084 - 9087 (2016/07/26)
Herein, we report the palladium-catalyzed direct arylation of unactivated aliphatic C?H bonds in free primary amines. This method takes advantage of an exo-imine-type directing group (DG) that can be generated and removed in situ. A range of unprotected aliphatic amines are suitable substrates, undergoing site-selective arylation at the γ-position. Methyl as well as cyclic and acyclic methylene groups can be activated. Furthermore, when aniline-derived substrates were used, preliminary success with δ-C?H arylation was achieved. The feasibility of using the DG component in a catalytic fashion was also demonstrated.
