122nd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentations for Young Scholars in Organic Division
Room No. Room 325A+B
Time THU 09:45-:
Code ORGN.O-4
Subject Synthesis of Chiral [1,4]-diazocines : Enantioselective Rhodium(II)-catalyzed [5+3] Cycloaddition
Authors Ju Young Lee, Eun Jeong Yoo*
Department of Applied Chemistry, Kyung Hee University, Korea
Abstract Eight-membered heterocycles are one of the most significant classes of compounds as it has been found in as key structural motif in a large number of biologically important natural products and pharmaceuticals. Among the established approaches including most popular ring-closing metathesis, Heck or other cross-coupling reactions for the synthesis of such medium-ring heterocycles the higher-order cycloaddition strategy is believed to be hard as it associated with unfavourable enthalpic and entropic parameters. As a consequence, the number of reports describing [5+3] cycloaddition to form eight-membered heterocycles are limited. Recently, our group disclosed a novel intermolecular rhodium(II)-catalyzed [5+3] cycloaddition between pyridinium zwitterions as 1,5-dipole equivalents and enol diazoacetates for the efficient formation of eight-membered heterocycles. Also, we have investigated the detail mechanistic insight of this reaction based on DFT study. Based on our previous results, we developed the asymmetric version of this interesting methodology using a chiral Rh(II)-catalyst and tuning the reaction condition. Despite this initial success, we were unable to apply this protocol as general basis. After extensive screening of the reaction conditions, we envisioned that some structural tuning is required for both the zwitterionic species and the diazo-substrate. In this symposium we will discuss our successful approach towards asymmetric [5+3]-cycloaddition between quinoline-based 1,5-dipole with vinyl diazoacetate partners.
E-mail ljy850706@naver.com