Highly chemoselective deoxygenation of N-heterocyclic N-oxides under transition metal-free conditions
Se Hyun Kim1, Ju Hyeon An1, Jun Hee Lee1
1Department of Advanced Materials Chemistry, Dongguk University Gyeongju Campus, Gyeongju 38066, Republic of Korea. leejunhee@dongguk.ac.kr.
Abstract:
Because their site-selective C-H functionalizations are now considered one of the most useful tools for synthesizing various N-heterocyclic compounds, the highly chemoselective deoxygenation of densely functionalized N-heterocyclic N-oxides has received much attention from the synthetic chemistry community. Here, we provide a protocol for the highly chemoselective deoxygenation of various functionalized N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst. Mechanistic studies imply that the excited state of the organophotocatalyst is reductively quenched by Hantzsch esters. This operationally simple technique tolerates a wide range of functional groups and allows high-yield, multigram-scale deoxygenation.
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