title: Brønsted acid-catalyzed α-halogenation of ynamides from halogenated solvents and pyridine-N-oxides.
abstract: The keteniminium ions generated from the protonation of ynamides formed reversible adducts with counter anions and pyridine-N-oxides as well as halogenated solvents. Above 80 °C, the halonium ions selectively undergo a rate-limiting attack by pyridine-N-oxides, leading to (E)-haloenamides in good yields.
authors.affiliation: Department of Chemistry and Center for New Directions in Organic Synthesis (CNOS), Research Institute for Natural Sciences, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea. sshin@hanyang.ac.kr.
authors.forename: Seung Woo
authors.identifier: http://orcid.org/0000-0002-2102-6504
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Chemistry and Center for New Directions in Organic Synthesis (CNOS), Research Institute for Natural Sciences, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea. sshin@hanyang.ac.kr.
authors.forename: Tae-Woong
authors.identifier: http://orcid.org/0000-0002-9623-0817
authors.initials: TW
authors.lastname: Um
authors.affiliation: Department of Chemistry and Center for New Directions in Organic Synthesis (CNOS), Research Institute for Natural Sciences, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Korea. sshin@hanyang.ac.kr.
authors.forename: Seunghoon
authors.identifier: http://orcid.org/0000-0003-1702-8918
authors.initials: S
authors.lastname: Shin