A mild and general set of metalation procedures for the functionalization of unsymmetrical azobenzenes using a commercially available continuous-flow setup is reported. The metalations proceed with TMPLi under convenient conditions (0 °C, 20 s), and various classes of electrophiles can be used. With sensitive substrates, an in situ trapping metalation in which TMPLi is added to a mixture of the azobenzene and ZnCl2 or MgCl2·LiCl was very effective for achieving high yields.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry