Visible-Light-Promoted Photoaddition of <i>N</i>-Nitrosopiperidines to Alkynes: Continuous Flow Chemistry Approach to Tetrahydroimidazo[1,2-<i>a</i>]pyridine 1-Oxides
Dilip V. Patil, Yulim Lee, Hun Young Kim, Kyungsoo Oh
Abstract
The photoaddition of N-nitrosopiperidines to terminal alkynes was effected under visible-light irradiation, in which a novel synthetic access to tetrahydroimidazo[1,2-a]pyridine 1-oxides was achieved via the dehydrogenative cycloisomerization of β-nitroso enamine intermediates. The decomposition pathways of N-nitrosamines, alkynes, and β-nitroso enamine intermediates were better handled in a continuous flow setting through the diffusion control of chemical species that negatively affected the formation of tetrahydroimidazo[1,2-a]pyridine 1-oxides under batch reaction conditions.
Topics & Concepts
ChemistryPyridineEnaminePhotochemistryDecompositionContinuous flowNitroso CompoundsNitrosoCycloisomerizationMedicinal chemistryOrganic chemistryCatalysisPhysicsMechanicsInnovative Microfluidic and Catalytic Techniques InnovationRadical Photochemical ReactionsSynthesis and Catalytic Reactions