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  • 09월 01일 18시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제118회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Base-Controlled Cu-Catalyzed Tandem Cyclization and Alkynylation for the Synthesis of Indoles and Indolizines

2016년 9월 1일 12시 08분 50초
ORGN.P-427 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 14일 (금요일) 11:00~12:30
저자 및
오경환, 김성민, 박선영, 박진균*
부산대학교 화학과, Korea
Over the last decade, transition metal-catalyzed aminometallation1 of alkynes has been widely used for the synthesis of heterocycles such as indoles and indolizines. A tandem reaction strategy has been used to access diversely functionalized N-heterocycles as well; utilizing a metal-bound intermediate generated in situ for the subsequent C-C coupling reaction with pre-chosen reagents.2,3 The procedure benefits from good atom and step economy, offers flexibility in constructing the organic backbone, and has excellent selectivity in C-C bond forming reaction. To date, while a few example of Rh and Pt catalysis are known for tandem addition reactions in the indole synthesis, most examples are limited to Pd catalysis for the synthesis of indoles and indolizines involving cycloisomerization, followed by C-C coupling reactions. These methods, however, require harsh reaction conditions and expensive metal and ligand. Interestingly, copper-catalyzed tandem C-C coupling reaction has rarely been explored despite of copper metal’s natural abundance and cheap price. Recently, we have developed a base-controlled Cu-catalyzed tandem cyclization/alkynylation of propargylic amines, which provides rapid access to functionalized indole and indolizine4 derivatives under mild reaction conditions. The reaction first proceeded via a 5-endo-dig aminocupration, followed by a coupling between the copper-bound intermediate and alkynyl bromide, to afford the products in good to excellent yields. The successful tandem reaction for excellent selectivity is attributed to the unique property of the bases, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and MTBD (7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene).