458-92-4Relevant articles and documents
Redox-Neutral TEMPO Catalysis: Direct Radical (Hetero)Aryl C?H Di- and Trifluoromethoxylation
Lee, Johnny W.,Lim, Sanghyun,Maienshein, Daniel N.,Liu, Peng,Ngai, Ming-Yu
supporting information, p. 21475 - 21480 (2020/10/02)
Applications of TEMPO. catalysis for the development of redox-neutral transformations are rare. Reported here is the first TEMPO.-catalyzed, redox-neutral C?H di- and trifluoromethoxylation of (hetero)arenes. The reaction exhibits a broad substrate scope, has high functional-group tolerance, and can be employed for the late-stage functionalization of complex druglike molecules. Kinetic measurements, isolation and resubjection of catalytic intermediates, UV/Vis studies, and DFT calculations support the proposed oxidative TEMPO./TEMPO+ redox catalytic cycle. Mechanistic studies also suggest that Li2CO3 plays an important role in preventing catalyst deactivation. These findings will provide new insights into the design and development of novel reactions through redox-neutral TEMPO. catalysis.
DIFLUOROMETHOXYLATION AND TRIFLUOROMETHOXYLATION COMPOSITIONS AND METHODS FOR SYNTHESIZING SAME
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Page/Page column 82, (2019/09/18)
The present invention provides a compound having the structure (I), a processing of making the compound; and a process of using the compound as a reagent for the difluoromethoxylation and trifluoromethoxylation of arenes or heteroarenes.
Iron-Catalyzed Isopropylation of Electron-Deficient Aryl and Heteroaryl Chlorides
Sanderson, James N.,Dominey, Andrew P.,Percy, Jonathan M.
, p. 1007 - 1017 (2017/03/27)
Traditional methods for the preparation of secondary alkyl-substituted aryl and heteroaryl chlorides challenge both selectivity and functional group tolerance. This contribution describes the use of statistical design of experiments to develop an effective procedure for the preparation of isopropyl-substituted (hetero)arenes with minimal isopropyl to n-propyl isomerization. The reaction tolerates electronically diverse aryl chloride coupling partners, with excellent conversion observed for strongly electron-deficient aromatic rings, such as esters and amides. Electron-rich systems, including methyl- and methoxy-substituted aryl chlorides, were found to be less reactive. Furthermore, the reaction was found to be most successful when heteroaryl chlorides were submitted to the cross-coupling protocol. By mapping substituent effects on reaction selectivity, we were able to show that electron-deficient aryl chlorides are essential for efficient coupling, and use electronic structure calculations to predict the likelihood of successful coupling through the estimation of the electron affinity of each aryl chloride. Moderate isolated yields were achieved with selected aryl chlorides, and moderate to good isolated yields were obtained for all the heteroaryl chlorides coupled. Excellent selectivity was observed when a 2,6-dichloroquinoline was used, allowing mono-substitution on a challenging substrate. (Figure presented.).