Protecting group directed asymmetric organocatalysis [3+2] cycloaddition of isocyanide and methyleneindolinone : stereoselective construction of spirocyclic oxindoles

• Main Author: Zhang, Xuan
• Other Authors: Zhong Guofu
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
• Online Access: http://hdl.handle.net/10356/39823
• Institution: Nanyang Technological University

The spiro[pyrrodilin-3,3’-oxindole] ring skeleton is a privileged structure with promising biological and pharmaceutical properties and only limited asymmetric synthetic approaches were reported due to the challenge in the synthesis of highly stereocontrolled quaternary carbon chiral centers. We developed a novel asymmetric synthesis of spirocyclic oxindoles via [3+2] cycloaddition of isocyanide and methyleneindolinone to afford adducts with two quaternary and one tertiary carbon stereocenters in moderate to good yield and excellent enantioselectivities. We also demonstrated that changing the protecting group of nitrogen atom in methyleneindolenone can result in change of the absolute configuration of desired spiro[pyrrodilin-3,3’-oxindole] core.