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Sonogashira Coupling (Cu/Amine‐Free) of ArBr/Cl in Aerobic Condition and N ‐ Benzylation of Aniline with Benzyl Alcohol Catalyzed by Complexes of Pd(II) with Sulfated/Selenated NHCs
Author(s) -
Dubey Pooja,
Singh Ajai K.
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201904819
Subject(s) - chemistry , sonogashira coupling , medicinal chemistry , iodide , aniline , catalysis , hexafluorophosphate , crystal structure , benzyl alcohol , amine gas treating , palladium , organic chemistry , ionic liquid
Abstract The moisture and air insensitive, and thermally stable [Pd( L1/L2 ‐H)Cl][PF 6 ] ( 1 / 2 ) and [Pd( L3 / L4 ‐HI)Cl 2 ] ( 3 / 4 ) catalyze N ‐benzylation of aniline (at 100 °C) and Sonogashira coupling of ArBr/Cl (at 80 °C) in the presence of KOH and K 2 CO 3 respectively. The optimum catalyst loading (mol %) is 0.02‐0.1 for the C−C coupling and 0.5 for N ‐benzylation. The 1–4 were found reusable. The L1 / L2 =3‐(1‐benzyl‐1 H ‐1,2,3‐triazol‐4‐yl)methyl)‐1‐(2‐(phenyl thio/seleno)ethyl)‐1 H ‐benzo[d]imidazol‐3‐ium hexafluorophosphate and L3 / L4 = 4‐methyl‐1‐(2‐(phenylthio/seleno)ethyl)‐1H‐1,2,4‐triazol‐4‐ium iodide are precursors of N ‐heterocyclic carbenes. Copper‐catalyzed click reaction gave L1 / L2 . The treatment of triazole with ClCH 2 CH 2 Cl, [PhS/Se] − Na + and MeI successively afforded L3 / L4 . The sequence of reactions of L1 ‐ L4 with Ag 2 O and [Pd(CH 3 CN) 2 Cl 2 ] (M : L=1 : 1) gave 1–4 . The L1‐L4 and 1–4 were characterized by elemental analyses, multi‐nuclei NMR, HR‐MS and single‐crystal structure ( 3 and 4 ). The geometry of Pd in 3 / 4 is nearly square planar. The bond distances (Å) in 3 / 4 are: Pd−S/Se, 2.3040(7)/2.402(2) and Pd−C, 1.961(3)/1.938(11).