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제124회 대한화학회 학술발표회, 총회 및 기기전시회 Direct Allylic C(sp3)–H Thiolation with Disulfides Enabled by Visible-Light Photoredox Catalysis

2019년 8월 21일 21시 12분 50초
ORGN.P-315 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 18일 (금요일) 11:00~12:30
Organic Chemistry
저자 및
Jungwon Kim, Byungjoon Kang, Soon Hyeok Hong1,*
Division of Chemistry, Seoul National University, Korea
1Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
In spite of the wide utility of allyl sulfides, the direct, catalytic allylic C(sp3)–H thiolation remains elusive. Here we report a direct allylic C(sp3)–H thiolation mediated by visible light photoredox catalysis. The use of in-situ generated thiyl radical from disulfide as a hydrogen atom transfer (HAT) reagent and coupling partner enabled selective cleavage of the allylic C(sp3)–H bond. The undesired hydrothiolation, a prevalent reaction from facile thiyl radical addition to olefins, was prevented by the immediate deprotonation of thiol under basic conditions. A wide range of diaryl disulfides and olefins participated in the reaction, producing allyl sulfides in high efficiency. Mechanistic investigations revealed the participation of the photocatalyst as a redox mediator, which was crucial for the transformation of the allyl radical into an allyl cation and further ionic coupling processes. Based on the mechanistic understanding, limitation in the synthesis of alkyl allyl sulfide was overcome with rationally designed, more electron-deficient unsymmetric disulfide, which makes the desired catalytic cycle operative.