64954-01-4Relevant academic research and scientific papers
A Practical Electrophilic Nitrogen Source for the Synthesis of Chiral Primary Amines by Copper-Catalyzed Hydroamination
Guo, Sheng,Yang, Jeffrey C.,Buchwald, Stephen L.
, p. 15976 - 15984 (2018)
A mild and practical method for the catalytic installation of the amino group across alkenes and alkynes has long been recognized as a significant challenge in synthetic chemistry. As the direct hydroamination of olefins using ammonia requires harsh conditions, the development of suitable electrophilic aminating reagents for formal hydroamination methods is of importance. Herein, we describe the use of 1,2-benzisoxazole as a practical electrophilic primary amine source. Using this heterocycle as a new amino group delivery agent, a mild and general protocol for the copper-hydride-catalyzed hydroamination of alkenes and alkynes to form primary amines was developed. This method provides access to a broad range of chiral α-branched primary amines and linear primary amines, as demonstrated by the efficient synthesis of the antiretroviral drug maraviroc and the formal synthesis of several other pharmaceutical agents.
Selective Hydrogen Transfer in N-(Diphenylmethyl)-1-phenylethan-1-imine
Li, J.,Shi, Y. B.,Xing, J. D.
, p. 589 - 597 (2021/06/02)
Abstract: Proton transfer processes mediate many organic reactions. How to realizestereochemical control of this process has always been a challenging topic inthe field of asymmetric catalysis. In this study, N-(diphenyl-methyl)-1-phenylethan-1-imine (Schiff base derivedfrom 2,2-diphenylethan-1-amine and acetophenone) was used as substrate, anddifferent near neutral solvents and various chiral metal complex catalysts wereused to carry out photoinduced C=N double bond transfer in the substrate underirradiation with a mercury ultraviolet lamp. The double bond transfer in thesubstrate molecule was highly selective. Solvents containing strongelectronegative atoms like oxygen and chlorine, such as alcohols, aldehydes, andcarbon tetrachloride, were more effective than other solvents under high lightintensity. The 1,3-proton transfer process involves photo-excitation of theSchiff base and coordination of the latter to the central metal atom of thechiral catalyst, so that the substrate molecule is placed in a stable chiralenvironment to form a transition state. The strongly electro-negative atom ofthe near-neutral solvent attracts the active α-hydrogen from the excited Schiffbase molecule to form a negatively charged delocalized π-bond structure. Thesubsequent proton addition yields more stable molec-ular structure to completethe selective proton transfer process. Among the examined chiral catalysts,divalent tin porphyrin was the most effective, and the product yield andenantiomeric excess were 98% and 91.49%, respectively. The describedphotoinduced C=N double bond transfer in N-(diphenylmethyl)-1-phenyl-ethan-1-imine is characterized by mildconditions (room temperature), high stereoselectivity, and simpleoperation.
