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다음주 정규세미나는 목요일(11월 27일) 4시 30분부터 330226호에서 더블헤더로 진행됩니다.               

많은 참석 부탁드립니다.

 
감사합니다.       

 

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정규세미나1.

 

제  목 : Stereodefined N,O- and O,O-acetals: Synthesis and Application

 

연  사 : 이영호 교수(POSTECH)

 

일  시 : 2014년 11월 27일(목) 오후 4시 30분

장  소 : 화학관 세미나실 (330226호실)

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Stereodefined N,O- and O,O-acetals: Synthesis and Application

 

  Developing new methodologies that can introduce molecular diversity with high chemical efficiency in a highly controlled manner represents a primary goal in synthetic organic chemistry. Due to their high reactivity and chemoselectivity, organometal catalysts may play a unique role. In this presentation, our achievements on the use of stereodefined allylic N,O-acetals and O,O-acetals as a key moiety. This unstable functional group was efficiently synthesized by the unprecedented Pd-catalyzed asymmetric hydroamination of allenes. Various examples on the aza- and oxacycle synthesis will be also introduced, which illustrate the use of these stereodefined N,O-acetals as a stereodiversity-generating element. This new synthetic method should be highly useful for both the target-oriented and the diversity-oriented synthesis of bioactive natural products and analogues.

 

 

References:

1. Kim, H.; Lim, W.; Im, D.; Kim, D.; Rhee, Y. H. Angew. Chem. Int., Ed. 2012,51, 12055.

2. Kim, H.; Rhee, Y. H. J. Am. Chem. Soc. 2012, 134, 4011.

3. Lee, J.; Gupta, S.; Jeong, W.; Rhee, Y. H.; Park, J. W.  Angew. Chem. Int., Ed. 2012,51, 10851.

4. Kang, S.; Kim, D.-g.; Rhee, Y. H, Chem. Eur-J.2014, in press.

5. Lim, W.;; Kim, J.; Rhee, Y. H,  J. Am. Chem. Soc. 2014, 136, 13618.

 

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정규세미나2.

 

제  목 : Iridium-catalyzed Borylation of Secondary C-H bonds Directed By a Hydrosilyl Group

연  사 : 조승환 교수(POSTECH)

 

일  시 : 2014년 11월 27일(목) 오후 5시 30분

장  소 : 화학관 세미나실 (330226호실)

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Iridium-catalyzed Borylation of Secondary C-H bonds Directed By a Hydrosilyl Group

Keywords     C-H functionalization, borylation, Iridium

 Iridium-catalyzed functionalization of C‒H bonds with bis(pinacolato)diboron (B₂pin₂) has become a practical method for the direct formation of boronate esters. Significant progress has been made on the borylation of sp² C−H bonds, but the borylation of sp³ C‒H bonds is less developed. Compared to the borylation of sp²C‒H bonds, the borylation of sp³ C‒H bonds typically requires high catalyst loadings and excess of the saturated substrates. The regioselectivity of the borylation of sp³ C‒H bonds strongly favors reaction at primary C‒H bonds, making the functionalization of secondary C‒H bonds challenging.  In this seminar, I will present a series of catalytic reactions that convert secondary sp³ C-H bonds of alkyl groups to C-B bonds.  These reactions occur through metal-boryl complexes and metal-silyl complexes.  This presentation will also include information on the properties of these complexes that lead to catalytic reactions and information on the properties and reactions of the organoboron product.