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

Late-stage functionalization (LSF) strategies, which favor large scope of products and time-efficient syntheses, are particularly attractive. While proficient, these approaches promote often specific reactivities at single site only. Herein, in the context of heterohelicene chemistry, metal-catalyzed decompositions of alpha-diazomalonates are shown to afford, step-by-step, multi-functionalized chiral diaza [4]helicenes. By selecting the catalyst, [CpRu(CH3CN)3][PF6] (Cp = cyclopentadienyl) or Rh2(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). Mechanism of formation and origin of selectivity are elucidated based on DFT calculations. Formation of products of tris- and tetra-malonate insertions can be further achieved thanks to the higher reactivity of rhodium carbenes. This multi-introduction of malonate groups is particularly useful to tune important properties of the [4]helicene core such as absorption, emission (quantum yield 5 to 22% and lifetime 3.0 to 8.4 ns, CH3CN) and Brønsted acidity (pKa 2•H+ to 6•H+, 6.63 to−0.42 and lower). TDDFT showcases the importance of conformations in the optical response. Cellular imaging studies evidence strong discriminations among various malonate esters or derived amides in the labelling of Hela-MZ cells.

Organizational unit

Laboratory of Professor Jérôme Lacour

Type

Dataset

DOI

10.26037/yareta:py3o7ztvrnfdtcatka6yfrz27e

License

Creative Commons Attribution 4.0 International

Keywords

Late-stage_Functionalization Metal_Catalyzed_Diazo_Decomposition [4]Helicenes C(sp2)-H_Insertion (Chir)Optical_Properties Brønsted_Acidity_Tuning