Chemo- and Regioselective Multiple C(sp2 )-H Insertions of Malonate Metal Carbenes for Late-Stage Functionalizations of Azahelicenes

Chiral quinacridines react up to four times, step-by-step, with alpha-diazomalonates under Ru-II and Rh-II catalysis. By selecting the catalyst, [CpRu(CH3CN)(3)][PF6] (Cp=cyclopentadienyl) or Rh-2(oct)(4), chemo and regioselective insertions of derived metal carbenes are achieved in favor of mono- or bis-functionalized malonate derivatives, respectively, (r.r.>49 : 1, up to 77 % yield, 12 examples). This multi-introduction of malonate groups is particularly useful to tune optical and chemical properties such as absorption, emission or Bronsted acidity but also cellular bioimaging. Density-functional theory further elucidates the origin of the carbene insertion selectivity and also showcases the importance of conformations in the optical response.