title: Synthesis of benzoxazoles via an amine-catalyzed [4 + 1] annulation.
abstract: An unprecedented simple pyrrolidine catalyzed [4 + 1] annulation reaction of ynals with N-protected-2-aminophenols is reported. The utilization of the unique property and reactivity of the C≡C triple bond in ynals leads to two consecutive conjugate addition reactions at the same β-position with pyrrolidine via iminium activation. The powerful cascade process affords a new alternative approach to biologically and synthetically important benzoxazoles in high yields (83-95%).
authors: Department of Chemistry and Chemical Biology, University of New Mexico , Albuqueruqe, New Mexico 87131-0001, United States, and School of Pharmacy, East China University of Science & Technology , Shanghai 200237, China.
authors: Aiguo
authors: A
authors: Song
authors: Xiaobei
authors: X
authors: Chen
authors: Xixi
authors: X
authors: Song
authors: Xinshuai
authors: X
authors: Zhang
authors: Shilei
authors: S
authors: Zhang
authors: Wei
authors: W
authors: Wang
mesh_terms: D000588:Amines / Q000737:chemistry*; D001583:Benzoxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D007097:Imines / Q000737:chemistry; D015394:Molecular Structure; D011759:Pyrrolidines / Q000737:chemistry*
chemical_list: D000588:Amines; D001583:Benzoxazoles; D007097:Imines; D011759:Pyrrolidines; C032519:pyrrolidine