imines or pyrrole compounds. Harnessing the power of photocatalysis, we accomplished a straightforward synthesis of 3-oxazolin-5-ones from redox-active esters and secondary nitrocompounds. Visible light-induced nondecarboxylative coupling of a redox-active ester, nitro aldol condensation, and subsequent visible light-induced N-oxide deoxygenation were accomplished within 2 h. The reaction mechanism was
Photoredox-Nickel Dual-Catalyzed <i>C</i>-Alkylation of Secondary Nitroalkanes: Access to Sterically Hindered α-Tertiary Amines
作者:Sina Rezazadeh、Maxwell I. Martin、Raphael S. Kim、Glenn P. A. Yap、Joel Rosenthal、Donald A. Watson
DOI:10.1021/jacs.2c13174
日期:2023.3.1
The preparation of tertiary nitroalkanes via the nickel-catalyzed alkylation of secondary nitroalkanes using aliphatic iodides is reported. Previously, catalytic access to this important class of nitroalkanes via alkylation has not been possible due to the inability of catalysts to overcome the steric demands of the products. However, we have now found that the use of a nickel catalyst in combination
Herein, by exploiting different activation modes of fluoroamides, we achieved α- and δ-C(sp3)–H alkylation of nitroalkanes with switchable regioselectivity. Cu catalysis enabled the interception of a distal C-centered radical by a N-centered radical to couple nitroalkanes and unactivated δ-C–H bonds. In addition, imines generated in situ by fluoroamides were trapped by nitroalkanes to realize the α-C–H
在此,通过利用氟酰胺的不同活化模式,我们实现了具有可切换区域选择性的硝基烷烃的α-和δ-C(sp 3 )–H烷基化。Cu 催化作用使得以 N 为中心的自由基拦截远端以 C 为中心的自由基,从而偶联硝基烷烃和未活化的 δ-C-H 键。此外,氟酰胺原位生成的亚胺被硝基烷烃捕获,实现酰胺的α-C-H烷基化。这两种可扩展的协议都具有广泛的底物范围和良好的官能团耐受性。