Asymmetric Organic Synthesis and Drug Synthesis Lab

[ACS Catalysis, 25-02-07: Synthesis of (Z)-Allylsilanes by Cu-Catalyzed Regioselective Protosilylation of Allenes via a Single-Electron Process]

Congrats~! Min and Seongha reported their works in ACS Catalysis under the supervision of Prof. Yunmi Lee (KW), Prof. Sangwon Seo and me. 

We developed the Cu-catalytic protocol which enables (Z)-selective formation of linear allylsilanes with a broad range of allenes. In contrast to the previous reports which led to (E)-allylsilanes with Cu catalyst, we chose the different approach to get the opposite forms, namely protosilylation rather than hydrosilylation. For the successful development, the most challenging part was the regioselective silacupuration of Cu-Si intermediate to an allene substrate. We found that silacupration of our system was occurred through a single-electron process due to the congested Cu center, which prohibited conventional 1,2-migratory insertion in other Cu systems. Our method is gram-scalable and tolerable to various kinds of functional groups (FGs), including free alcohol bearing acidic protons. The demonstration of allysilanes' synthetic applications was highlighted the synthetic utility of our protocols. 

[ACS Catalysis, 24-04-05: Ni-Catalyzed Mono- and Dihydrosilylation of Aliphatic Alkynes in Aqueous and Aerobic Conditions]

Congrats~! Chanmi reported her works in ACS Catalysis in collaboration with Prof. Sung You Hong's research group in UNIST. 

We developed the method of preparing 1,1-disilanes from terminal alkynes under aqueous and air conditions. By sequential hydrosilylation with Ph2SiH2 and PhMeSiH2, the chiral center bearing two C-Si bonds can be formed. Experimentally, we proved the existence of Ni(+2) intermediates including LNi(acac)H by XRD and HRMS analysis. Computational studies based on the seminal references revealed that LNi(+1)H would be formed (other forms could not explain the regioselectivity of experimental results at all). Chanmi was super amazing: 1) optimization of mono- and dihydrosilylation of alkynes, 2) screening of substrate scope, 3) control experiments and mechanistic studies, 4) synthetic applications: She did all jobs by herself and finally nailed it!!!  

To Dr. Jaesung Kwak and Prof. Sangwon Seo, I am  deeply grateful for their excellent works for computations. I also appreciate Prof. Wonyoung Choe for XRD analysis. 

[Organic Letters, 23-12-15: Cu-Catalyzed Synthesis of 2-Silyl-1,3-butadienes from Allenols and Applications to One-Pot Synthesis of Tetrasubstituted Arylsilanes]

Congrats~! Yurim and Yeonjoo reported their work in Organic Letters in collaboration with Prof. Yunmi Lee's research group in Kwangwoon University. 

We developed the method of preparing 2-Si-1,3-butadiene analogues from easily accessible allenols in high yields. 2-Si-1,3-dienes, known as versatile dienes for Diels-Alder reactions, indeed are good for Diels-Alder reaction with activated dienophiles. By the combination of Cu-catalyzed silylation, Diels-Alder reaction, and mild oxidation in the single reaction apparatus, we could showcase the synthetic utility by the one-pot synthesis of tetrasubstituted arylsilanes from allenols. 

To Hwiwoong Lee and Telma Kamranifard, as collaborators, we are  deeply grateful for their excellent works under the supervision of Prof. Yunmi Lee.  

[ACS Catalysis, 23-02-17: Synthesis of α-Borylmethyl-(E)-Allylborons via Cu-Catalyzed Diboration of 1-Substituted Allenols and Their Application in Stereoselective Aldehyde Allylation]

Congrats~! Yeonjoo and Yurim reported their work in ACS Catalysis in collaboration with Prof. Yunmi Lee's research group in Kwangwoon University. We are also grateful for great works of DFT computations by JuHyung Lee under the supervision of Prof. Joongoo Kang in our institute. 

This article includes various sorts of mechanstic aspects as well as synthetic views about preparation and applications of diborons, so we do believe that it should be helpful in fields of organoborons chemistry.