Facile access to libraries of diversely substituted 2-aryl-benzoxazoles/benzothiazoles from readily accessible aldimines via cyclization/cross coupling in imidazolium-ILs with Pd(OAc)2 or NiCl2 (dppp) as catalyst. Issue 6 (6th February 2020) - Malunavar, Shruti S.
Graphical abstract: Highlights: Libraries of diversely substituted 2-aryl-/heteroaryl-benzoxazoles/benzothiazoles from readily available aldimines. Two-step process of cyclization and cross-coupling. Catalysis by either Pd or Ni. One-pot sequential process. Ionic liquids as solvent with recycling/reuse potential. Abstract: A two-step protocol involving Pd-catalyzed cyclization of readily accessible p -bromophenyl-aldimines to 2-bromophenyl-benzoxazole/benzothiazole in [BMIM][PF6 ] or [BMIM][BF4 ] as solvent, followed by the Suzuki, Heck, and Sonogashira cross-coupling reactions catalyzed by Pd or Ni is described that generates libraries of diversely substituted 2-aryl-/heteroaryl-benzoxazoles/benzothiazoles in respectable isolated yields under mild reaction conditions. The feasibility to perform the two-steps in sequence in one-pot starting from the aldimines is also demonstrated and the potential for recycling/reuse of the IL solvent is also shown.