Asymmetric Synthesis of Spirocyclopentane Oxindoles Containing Four Consecutive Stereocenters and Quaternary α-Nitro Esters via Organocatalytic Enantioselective Michael-Michael Cascade Reactions

Prakash D Chaudhari; Bor-Cherng Hong; Chao-Lin Wen; Gene-Hsiang Lee

doi:10.1021/acsomega.8b03049

Asymmetric Synthesis of Spirocyclopentane Oxindoles Containing Four Consecutive Stereocenters and Quaternary α-Nitro Esters via Organocatalytic Enantioselective Michael-Michael Cascade Reactions

ACS Omega. 2019 Jan 9;4(1):655-667. doi: 10.1021/acsomega.8b03049. eCollection 2019 Jan 31.

Authors

Prakash D Chaudhari¹, Bor-Cherng Hong¹, Chao-Lin Wen¹, Gene-Hsiang Lee²

Affiliations

¹ Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan, ROC.
² Instrumentation Center, National Taiwan University, Taipei 106, Taiwan, ROC.

Abstract

An enantioselective domino Michael-Michael reaction of nitroolefins and 2-nitro-3-arylacrylates has been established, which provided a series of spirocyclopentane oxindoles with four consecutive stereocenters including quaternary α-nitro esters with good yields (up to 73%) and excellent enantioselectivities (up to 97% ee). The reaction was realized and optimized with the aid of a chiral squaramide-amine catalyst. The structures of 11 products were confirmed by single-crystal X-ray diffraction analysis.