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  • 09월 10일 16시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제124회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Site-Selective C–H Acylation of Pyridine Scaffolds by Photoredox Catalysis

2019년 9월 9일 10시 28분 54초
ORGN.P-452 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 18일 (금요일) 11:00~12:30
Organic Chemistry
저자 및
Sungwoo Jung, Sungwoo Hong*
Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea

Despite several recent advances about acylation of pyridine moieties, existing methods remain limited mainly to the introduction of the acyl group to the C2-position of the pyridine scaffold, and the C4-acylation of pyridines has yet to be reported with meaningful selectivity. Herein, we developed a new strategy for visible-light-promoted site-selective C–H acylation of pyridinium salts by employing N-methoxy- or N-aminopyridinium salts, providing a powerful synthetic tool for accessing highly valuable C2- and C4-acylated pyridines. The methoxy or amidyl radicals photocatalytically generated from the pyridinium salts can abstract the hydrogen atom from readily available aldehydes to form acyl radicals, which can engage in addition to pyridinium derivatives. Remarkably, the use of N-methoxypyridinium salts preferentially gives the C2-acylated pyridines, and the site selectivity can be changed from C2- to C4-position by using N-aminopyridinium salts. The utility of this method was further demonstrated by the late-stage modification of complex biorelevant molecules and by application of acyl radicals to photoredox-catalyzed radical cascade reactions.