Ru(II)-catalyzed regioselective [3+2] spiroannulation of 4-arylquinazolin-2(1H)-ones with ynones

A novel spiroannulation reaction between 4-arylquinazolinones and ynones has been developed to produce highly rigid spiroquinazolinone scaffolds through a [3+2] spirocyclization utilizing a catalytic amount of Ru(II) complex. This innovative strategy generates a broad spectrum of rigid spiro compounds in excellent yields with significant regioselectivity. Importantly, this process involves the C H functionalization of aryl (sp2) H bond followed by a nucleophilic addition of alkenyl ruthenium to imine functionality • First report on the synthesis of spiroquinazolinones with unsymmetrical alkynes. • Highly regioselective for the construction of spiroheterocycle frameworks. • Works well with a wide range of substrates and compatible with various functional groups. • Generates a novel class of highly rigid spiro scaffolds in excellent yields.