Loading...
2016.09.20 16:37

[Thu. 22 Sep. 2016] Prof. Anna Lee/Organocatalyzed Asymmetric Reactions

?

Shortcut

PrevPrev Article

NextNext Article

+ - Up Down Comment Print
?

Shortcut

PrevPrev Article

NextNext Article

+ - Up Down Comment Print
Extra Form
Speaker Prof. Anna Lee
Date Thursday 22 September 2016
Time 5:00pm
Venue #331, Asan Hall, College of Science

Organocatalyzed Asymmetric Reactions

 

 

The Catalytic Asymmetric Knoevenagel Condensation: The Knoevenagel condensation reaction developed by Emil Knoevenagel in 1896 is a powerful and efficient carbon-carbon bond forming reaction, but also the root of aminocatalysis. Remarkably though, while the Knoevenagel reaction, as the historic basis of all aminocatalyzed processes, has been incorporated into asymmetric organocascades and domino reactions, and even chiral auxiliary derived malonates have been studied, a variation in which the Knoevenagel reaction itself is utilized to establish asymmetry remained elusive. The main problems of the reaction were reactivity and stereoselectivity issues as well as the formation of by-products. The goal of this work was to develop the first enantioselective Knoevenagel condensation reaction using a novel chiral amine catalyst based on a dynamic kinetic resolution (DKR). Various chiral amine catalysts were synthesized, and we found that modified cinchona based amine catalysts provided the desired product in high yield and enantioselectivity.

 

figure.PNG

 

A Cooperative N-Heterocyclic Carbene/Chiral phosphate Catalysis System for Allenolate Annulations: NHC-catalyzed homoenolate additions to various electrophiles represent an enabling class of transformations that have been employed for the construction of complex hetero- and carbocyclic system through unconventional Umpolung reactivity. Recently, our group developed Lewis acid/NHC cooperative catalysis to develope novel transformations. In this study, we have extended the scope of cooperative catalysis by employing chiral phosphoric acids for the first time and this novel cooperative catalysis was applied to the challenging allenolate annulation reaction (Figure 1). A limited number of reports of NHC-catalyzed homoenolate additions involving alkynyl aldehydes have appeared. We have developed a highly efficient asymmetric [3+2] annulation reaction of alkynyl aldehydes withα-ketoesters via NHC/chiral phosphate cooperative catalysis.

 

figure2.PNG

 

 

 

 

References

1. Lee, A.; Michrowska, A.; S.-Mosse, S.; List, B., Angew. Chem. Int. Ed. 2011, 50, 1707.

2. Lee, A.; Reisinger, C.; List, B., Adv. Synth. Catal. 2012, 354, 1701.

3. Lee, A.; Scheidt, K. A., Angew. Chem. Int. Ed. 2014, 53, 7594.

4. Lee, A.; Younai, A. ; Price, C. K. ; Izquierdo, J. ; Mishra, R. K. ; Scheidt, K. A., J. Am. Chem. Soc. 2014,136, 10589.

5. Lee, A.; Scheidt, K. A., Chem. Commun. 2015, 51, 3407.

 

 

Prof. Anna Lee

Myongji University, Department of Chemistry, Yongin, Korea

 

 


  1. Fall semester 2016 Seminar Schedule

    -
    -
    Read More
  2. Spring semester 2017 Seminar Schedule

    -
    -
    Read More
  3. [Fri. 17 Mar. 2017] 9th RINS Symposium

    -
    Fri. 17 Mar. 2017
    Read More
  4. [Thu. 27 Apr. 2017] Seminar was canceled!

    -
    -
    Read More
  5. [Wed. 5 July. 2017] Seminar is canceled!

    -
    -
    Read More
  6. 7th Jilin-Korea-Waseda Alliance Annual Symposium

    -
    August 17 ~ 19, 2017
    Read More
  7. Fall semester 2017 Seminar Schedule

    -
    -
    Read More
  8. Fall semester 2018 Seminar Schedule

    -
    -
    Read More
  9. Spring semester 2019 Seminar Schedule

    -
    -
    Read More
  10. Announcements Graduate Seminar Spring Semester 2021

    .
    .
    Read More
  11. Announcement for Graduate Seminar Class, Fall Semester 2020

    Announcement for Graduate Seminar Class, Fall Semester 2020
    Announcement for Graduate Seminar Class, Fall Semester 2020
    Read More
  12. [October 31. 2019] Engineering energy band structures in organic and hybrid semiconductor devices using non-conjugated polyelectrolyte films

    Asst. Prof. Bright Walker(Kyung Hee University)
    Thu. 31 October. 2019
    Read More
  13. June 10th (Fri) Graduate Seminar / Bing Zhang, Ph.D.

    Bing Zhang, Ph.D. (Baylor College of Medicine)
    Fri, Jun 10, 2022
    Read More
  14. 2022 International Symposium on Bioactive and Bioengineering Materials

    BK21 Chemistry Education Research Center
    November 22, 2022 (Tuesday)
    Read More
  15. 2022 International Symposium on Chemical Applications of Machine Learning

    BK21 Chemistry Education Research Center
    November 11, 2022 (Fri)
    Read More
  16. 2023 Germany-Korea On-Site Plenary Discussion on Computational Electrochemistry

    BK21 Chemistry Education Research Center
    April 17, 2023 (Mon)
    Read More
  17. [October 10, 2017] Novel Terahertz Spectroscopies

    Director Mischa Bonn
    Tue, October 10, 2017
    Read More
  18. [August 14. 2019] Principle of Semiconductor Quantum Cascade Laser and It’s Application to Chemical Gas Detection

    Dr. Byeong-il Seo(Agency for Defense Development)
    Wed. 14 August. 2019
    Read More
  19. [October 25, 2017] Ultrafast electron microscopy: applications in chemical and materials sciences

    Dr. Byung-Kuk Yoo
    October 25, 2017
    Read More
  20. May 11, 2023 (Thu) Dr. Changyeol Lee

    Dr. Changyeol Lee (Advanced Photonics Research Institute GIST)
    Thursday, May 11, 2023
    Read More
Board Pagination ‹ Prev 1 2 3 4 5 6 7 8 Next ›
/ 8

Designed by sketchbooks.co.kr / sketchbook5 board skin

나눔글꼴 설치 안내


이 PC에는 나눔글꼴이 설치되어 있지 않습니다.

이 사이트를 나눔글꼴로 보기 위해서는
나눔글꼴을 설치해야 합니다.

설치 Cancel

Sketchbook5, 스케치북5

Sketchbook5, 스케치북5

Sketchbook5, 스케치북5

Sketchbook5, 스케치북5

Department of Chemistry, Korea University, Tel) +82-2-3290-3120
145 Anam-ro Seongbuk-gu Seoul, 02841, Republic of Korea
Copyright(c) 2014 KOREA UNIVERSITY DEPARTMENT of CHEMISTRY. All right reserved.