title: Transition from π radicals to σ radicals: substituent-tuned cyclization of hydrazonyl radicals.
abstract: Hydrazonyl radicals are known for their p-electronic structures; however, their s-electronic structures have not been reported as yet. Herein, we show that readily accessible b,g- and g,d-unsaturated N-trichloroacetyl and Ntrifluoroacetyl hydrazones can be conveniently converted into hydrazonyl s radicals, which subsequently undergo 5-exo-trig radical cyclization at the N1 or N2 atom to form pyrazolines and azomethine imines, respectively.
authors.forename: Xiao-Yong
authors.initials: XY
authors.lastname: Duan
authors.forename: Neng-Neng
authors.initials: NN
authors.lastname: Zhou
authors.forename: Ran
authors.initials: R
authors.lastname: Fang
authors.forename: Xiu-Long
authors.initials: XL
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Bing
authors.initials: B
authors.lastname: Han