Suk Hun Lee

Cross-Coupling of Acrylamides and Maleimides under Rhodium Catalysis: Controlled Olefin Migration

The rhodium(III)-catalyzed direct cross-coupling reaction of electron-deficient acrylamides with maleimides is described. This protocol displays broad functional group tolerance and high efficiency, which offers a new opportunity to access highly substituted succinimides. Dependent on the substituent positions of acrylamides and reaction conditions, olefin migrated products were obtained with high regio- and stereoselectivity.

Rhodium(III)-Catalyzed C(sp3)–H Alkylation of 8-Methylquinolines with Maleimides

The rhodium(III)-catalyzed cross-coupling reaction of 8-methylquinolines and maleimides is described. In contrast to the C(sp(2))-H functionalization, a first catalytic functionalization of sp(3) C-H bonds with maleimides is reported. This protocol provides a facile access to various succinimide scaffolds on 8-methylquinolines via a direct C-H cleavage approach.

Ru(II)-Catalyzed C–H Aminocarbonylation of N-(Hetero)aryl-7-azaindoles with Isocyanates

The ruthenium(II)-catalyzed C-H aminocarbonylation of N-(hetero)aryl-7-azaindoles with isocyanates is described. The excellent site selectivity at the ortho-position within the N-(hetero)aryl ring was observed to provide ortho-amidated N-(hetero)aryl-7-azaindoles under the mild reaction conditions. The resulting 7-azaindole derivatives can be readily transformed into 7-azaindoles containing carboxylic acid and alkyl amine functional groups.

Synthesis of TMPA Derivatives through Sequential Ir(III)-Catalyzed C–H Alkylation and Their Antidiabetic Evaluation

The synthesis and antidiabetic evaluation of ethyl 2-[2,3,4-trimethoxy-6-(1-octanoyl)phenyl]acetate (TMPA) and its structural analogs are described. The construction of TMPA derivatives has been successfully achieved in only two steps, which involve the iridium(III)-catalyzed α-alkylation of acetophenones with alcohols and the ketone-directed iridium(III)- or rhodium(III)-catalyzed redox-neutral C–H alkylation of α-alkylated acetophenones using Meldrum’s diazo compounds. This synthetic protocol efficiently provides a range of TMPA derivatives with site selectivity and functional group compatibility. In addition, the site-selective demethylation of TMPA derivative affords the naturally occurring phomopsin C in good yield. Moreover, all synthetic compounds were screened for in vitro adenosine 5′-monophosphate-activated protein kinase (AMPK) activation using HepG2 cells. Furthermore, TMPA (5ac) and 5cd showing the most potent AMPK activation were treated for the in vivo antidiabetic experiment. Notably, our synthetic compound 5cd was found to display the powerful antidiabetic effect, stronger than that of metformin and TMPA (5ac).

CCDC 1556654: Experimental Crystal Structure Determination

Related Article: Hyunjung Oh, Jihye Park, Sang Hoon Han, Neeraj Kumar Mishra, Suk Hun Lee, Yongguk Oh, Mijin Jeon, Gyeong-Joo Seong, Ka Young Chung, In Su Kima|2017|Tetrahedron|73|4739|doi:10.1016/j.tet.2017.06.052