Iminoxyl Radical-Promoted Dichotomous Cyclizations: Efficient Oxyoximation and Aminooximation of Alkenes
摘要:
A novel iminoxyl radical-involved metal-free approach to vicinal oxyoximation and aminooximation of unactivated alkenes is developed. This method utilizes the dichotomous reactivity of the iminoxyl radical to furnish a general difunctionalization on alkenes using simple tert-butyl nitrite (TBN) as the iminoxyl radical initiator as well the carbon radical trap. By using this protocol, oxime featured 4,5-dihydroisoxazoles and cyclic nitrones were facilely prepared from beta,gamma- and gamma,delta-unsaturated ketoximes, respectively.
Transition from π Radicals to σ Radicals: Substituent-Tuned Cyclization of Hydrazonyl Radicals
作者:Xiao-Yong Duan、Neng-Neng Zhou、Ran Fang、Xiu-Long Yang、Wei Yu、Bing Han
DOI:10.1002/anie.201309918
日期:2014.3.17
Hydrazonylradicals are known for their π‐electronic structures; however, their σ‐electronic structures have not been reported as yet. Herein, we show that readily accessible β,γ‐ and γ,δ‐unsaturated N‐trichloroacetyl and N‐trifluoroacetyl hydrazones can be conveniently converted into hydrazonylσradicals, which subsequently undergo 5‐exo‐trig radicalcyclization at the N1 or N2 atom to form pyrazolines