Tandem dual C(sp^3)-H/C(sp^2)-H functionalization: a radical cyclization of 2-isocyanobiphenyl with ether to 6-alkylated phenanthridine

1 General experimental details 1H NMR and 13 C NMR spectra were measured on 400 MHz spectrometer, using CDCl3 as the solvent with tetramethylsilane(TMS) as the internal standard at room temperature. Chemical shifts(δ) are given in ppm relative to TMS, the coupling constants J are given in Hz. HRMS were recorded on a TOF LC/MS equipped with electrospray ionization(ESI) probe operating in positive or negative ion mode.

A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformation, which comprised the functional- ization of two C-H bonds： the sp3 C-H of ether and sp2 C-H of phenyl group. The kinetic isotope effect （KIE） revealed that the cleavage of sp3 C-H bond would be involved in the rate-determining step.