YOSHIKAI Naohiko

Associate Professor
National Research Foundation (NRF) Fellow

Education: B.Sc., M.Sc., Ph.D., University of Tokyo

Research Area: Synthetic and Physical Organic Chemistry; Catalysis; Organometallic Chemistry

Phone: (65) 6592 7768

E-mail: nyoshikai@ntu.edu.sg

Webpage: http://www3.ntu.edu.sg/home/nyoshikai/yoshikai_group/Home.html



Research Interest

Our major research interests focus on the development and mechanistic study of novel transition metal-catalyzed chemical transformations and their applications to the synthesis of interesting target molecules. Our research programs are primarily driven by our desire to uncover previously unknown chemical reactivities of elements and molecules by design, and to exploit such reactivities to develop highly efficient, mild, and selective organic reactions. Another important driving force is our interest in functional molecules, pi-conjugated molecules in particular. We develop our catalysts and reactions to allow us to access structurally and optoelectronically interesting compounds via unique and efficient routes. Some of our current research activities are summarized below.

Catalytic C–H Bond Functionalization
Transition metal-catalyzed functionalization reactions of C–H bonds have attracted much interest during the last decades as straightforward and economical alternatives to those relying on prefunctionalized substrates. While the majority of C–H functionalization catalysts have been based on noble second-row transition metals, first-row transition metals have not been extensively exploited regardless of their potential as cost-effective catalysts. Over the past few years, our group has pioneered cobalt catalysiss for C–H bond functionalization, and has been rapidly expanding its scope. We have thus far developed chelation-assisted and heteroatom-directed C–H alkenylation and alkylation reactions using alkynes and alkenes, where cobalt catalysts not only serve as mild and inexpensive alternatives to noble metal catalysts but also often exhibit unique reactivities and selectivities.

Transition Metal Catalysis of Main Group Organometallics
Regardless of the emergence of C–H functionalization, there exist some important molecular skeletons that are difficult to be accessed by this approach. To allow for the synthesis of such molecules, we have been developing new C–C bond forming reactions via transition metal catalysis of main group organometallics.

Novel Synthetic Routes to Conjugated Systems
We have been developing our catalytic reactions not only to explore novel chemical reactivities but also to aim at the synthesis of structurally and optoelectronically interesting molecules that could have potential applications as organic materials and catalyst architectures. Synthesis of such molecules based on our own and other synthetic methodologies are currently in progress.

 


Selected Publications

  1. Cobalt-Catalyzed, Room-Temperature Addition of Aromatic Imines to Alkynes via Directed C–H Bond Activation, Lee, P.-S.; Fujita, T.; Yoshikai, N. J. Am. Chem. Soc. 2011, 133, 17283-17295..

  2. Cobalt-Phenanthroline Catalysts for the ortho Alkylation of Aromatic Imines under Mild Conditions, Gao, K.; Yoshikai, N. Angew. Chem. Int. Ed. 2011, 50, 6888-6892.

  3. Cobalt-Xantphos-Catalyzed, LiCl-Mediated Preparation of Arylzinc Reagents from Aryl Iodides, Bromides, and Chlorides, Jin, M.-Y.; Yoshikai, N. J. Org. Chem. 2011, 76, 1972-1978 (Featured Article).

  4. Regioselectivity-Switchable Hydroarylation of Styrenes, Gao, K.; Yoshikai, N. J. Am. Chem. Soc. 2011, 133, 400-402.

  5. Cobalt-Catalyzed Addition of Azoles to Alkynes, Ding, Z.; Yoshikai, N. Org. Lett. 2010, 12, 4180-4183.

  6. Cobalt-Catalyzed Hydroarylation of Alkynes through Chelation-Assisted C–H Bond Activation, Gao, K.; Lee, P.-S.; Fujita, T.; Yoshikai, N. J. Am. Chem. Soc. 2010, 132, 12249-12251 (Highlighted in Synfacts 2010, 1410).