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  • 02월 19일 10시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제121회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Iridium-catalysed arylation of C-H bonds enabled by oxidatively induced reductive elimination

2018년 3월 12일 15시 36분 20초
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목 10시 : 23분
KCS - Oral Presentation for 2018 DOW Chemical Korea Award
저자 및
KWANGMIN SHIN, Yoonsu Park, Mu-Hyun Baik*, Sukbok Chang*
Center for Catalytic Hydrocarbon Functionalization, Institute for Basic Science, Korea
Direct arylation of C–H bonds is in principle a powerful way of preparing value-added molecules that contain carbon−aryl fragments. Unfortunately, currently available synthetic methods are not sufficiently effective to be practical alternatives to conventional cross-coupling reactions. We propose that the main problem lies in the late portion of the catalytic cycle where reductive elimination gives the desired C–C bond. Based on this hypothesis, a new strategy is implemented where the Ir(III) center of the key intermediate is oxidized to Ir(IV). Density functional theory calculations indicate that the reductive elimination barrier is reduced by nearly 19 kcal/mol when the metal is oxidized. Various experiments, including cyclic voltammetry and EPR analysis, confirm this prediction affording a new methodology capable of efficiently and directly arylating C–H bonds at room temperature with a broad substrate scope and in good yields. This work highlights how the oxidation states of intermediates can be targeted deliberately to rationally catalyze an otherwise impossible reaction.