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  • 02월 28일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제123회 대한화학회 학술발표회, 총회 및 기기전시회 Generation of Dienolonium Species from Brønsted Acid Catalyzed Oxidation of Enynamides by DMSO: Remote Functionalizations with Carbon and Heteronucleophiles

2019년 2월 13일 22시 44분 58초
ORGN.P-306 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
4월 18일 (목요일) 11:00~12:30
Organic Chemistry
저자 및
Huong Quynh Nguyen , Seunghoon Shin*
Department of Chemistry, Hanyang University, Korea

Recently we have developed a robust Brønsted acid-catalyzed activation of ynamides enabling oxidative coupling of diverse carbon nucleophiles.1 As an extension, we envisioned the oxidation of enynamide that would represent an umpolung of silyl dienol ethers in Mukaiyama alkylation. Employing DMSO as the terminal oxidant, oxidative coupling of enynamides efficiently furnished γ-substituted-α,β-unsaturated imides. Furthermore, not only carbon- but heteronucleophiles, such as alcohol, thiol, hydrazides could be employed in this oxidation protocol. In Hammett analysis, the reaction displayed a linear correlation with σ+ parameters with ρ = -1.3 ~ -3.1, indicating the reaction proceeds through a cationic dienolonium intermediate, and the origin of the remote site-selectivity could be ascribed to the charge-development at the terminal carbon. Eyring analysis led us to identify the formation of keteniminium ion as the rate-determining step.2 References 1. a) D. V.Patil, S. W. Kim, Q. H. Nguyen, H. Kim, S. Wang, T. Huang, S. Shin, Angew. Chem. Int. Ed. 2017, 56, 3670; b). S.W. Kim, T.W. Um, S. Shin, Chem. Commun. 2017, 53, 2733. 2. Q. H. Nguyen, N. H. Nguyen, H. Kim, Shin, S. manuscript in preparation.