Seminar

Seminar

[세미나 공지] - 2014년 3월 20일(목)

  • POSTED DATE : 2014-03-17
  • WRITER : 관리자
  • HIT : 2417
  • DATE : 2014-03-20
  • PLACE : 330226호실

3월 20일 목요일에 화학과 정규세미나가 개최됩니다.

많은 참석 부탁드립니다.
감사합니다.

 

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제  목 : 1-Sulfonyl-1,2,3-triazole: precursors for Rh(II)-azavinyl carbenes

 

연  사 : 유은정 교수(강원대학교)
 

일  시 : 2014년 3월 20일(목) 오후 4시 30분


장  소 : 화학관 세미나실 (330226호실)

 

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1-Sulfonyl-1,2,3-triazole: precursors for Rh(II)-azavinyl carbenes

Eun Jeong Yoo

Department of Chemistry, Kangwon National University, Chuncheon 200-701, Republic of Korea

E-mail: ejyoo@kangwon.ac.kr

 

While the reaction of aryl azide with 1-alkyne affords stable 1,2,3-triazole at room temperature, the employment of e-deficient sulfonyl azide resulted in apparently different outcomes because the stability of 1,2,3-triazoles is affected by the substituents at the N1 atom of triazole cycle. Triazoles bearing a sulfonyl group at the N1 atom exist in equilibrium with diazoimine tautomer, and thus chemists took advantage of this process by trapping diazoimine with a Rh(II) catalyst to produce the Rh(II) azavinyl carbenes. Undoubtedly, development of new method to access Rh(II) carbene species, readily prepared from 1-sulfonyl-1,2,3-triazole, could expand the scope of carbene chemistry.

In this seminar, the new reactivities of Rh(II) azavinyl carbenes toward carbonyl functional group, especially benzamides, will be presented. This catalytic reaction for the synthesis of Z-selective endiamines has a broad substrate scope with an excellent functional group tolerance even on a gram scale. Since amino moiety of the obtained endiamine product could be selectively removed by treating with NaBH4 to form Z-enamides, the developed routes are highly versatile and have great potential as a synthetic tool.

Next, we disclose a protocol for N-H insertion of Rh(II) azavinyl carbenes with carbazoles. As opposed to 1,1-insertions typically observed with conventional donor-acceptor carbenes, these reactions proceed via an ylide intermediate followed by a stereospecific proton transfer.