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。
Counterattack reagents: Thiosilanes in the conversion of nitro compounds to thiohydroxamic acids and thiohydroximates
作者:Jih Ru Hwu、Shwu-Chen Tsay
DOI:10.1016/s0040-4020(01)89057-8
日期:——
Mono-deoxygenation of Nitroalkanes, Nitrones, and Heterocyclic <i>N</i>-Oxides by Hexamethyldisilane through 1,2-Elimination: Concept of “Counterattack Reagent”
作者:Jih Ru Hwu、Wen Nan Tseng、Himatkumar V. Patel、Fong Fuh Wong、Den-Nan Horng、Ben Ruey Liaw、Lung Ching Lin
DOI:10.1021/jo981054i
日期:1999.4.1
Transformation of secondary nitroalkanes to ketoximes was achieved in 40-73% yields by treatment of the corresponding nitronate anions with hexamethyldisilane. In this new mono-deoxygenation process, hexamethyldisilane acted as a "counterattack reagent". The conversion of nitrones to imines was also achieved in 82-88% yields by use of trimethylsilyllithium. Similarly, heterocyclic N-oxides were converted to the corresponding N-heterocycles in 73-86% yields. These deoxygenation processes presumably involve a 1,2-elimination.
BRAENDLI, U.;EVER, M.;SEEBACH, D., CHEM. BER., 1986, 119, N 2, 575-588