Pd-Catalyzed C–H Annulation of Five-Membered Heteroaryl Halides with Norbornene Derivatives
作者:Birakishore Padhi、Geunhee Kang、Eunmin Kim、Jeongmin Ha、Hyun Tae Kim、Jeewoo Lim、Jung Min Joo
DOI:10.1021/acscatal.9b05177
日期:2020.2.7
Complementary to Catellani-type reactions and 1:1 coupling of six-membered halo(hetero)arenes and norbornene (NBE) derivatives, Pd-catalyzed 1:2 coupling of five-membered haloheteroarenes with NBEs was achieved to afford rigid nonplanar heterocycles. Pyrazole, thiophene, furan, and indole underwent exo- and trans-selective annulation. Two strained alkene groups of the resulting products were further
isomers. The cup-shaped syn cyclotrimers 3a−d exhibit highelectrondensitywithin the cavity as determined by AM1 semiempirical calculations of their electrostatic potential surfaces and are valuable substrates for supramolecular chemistry. As an example, it is shown that fullerene C60 is drawn into solution in acetonitrile by complexation with both the syn and anti trimer of benzonorbornadiene 3a.
aromatic unit, benzene, naphthalene or phenanthrene, fused to one of the NBD double bonds, while the carbon atoms of the other double bond are functionalized with donor and acceptorgroups. The synthesis protocols involve functionalization of benzo-fused NBDs with bromo/chloro substituents followed by a subjection of these intermediates to a cyanation reaction (introducing a cyano acceptorgroup) followed