Substituent and Lewis Acid Promoted Dual Behavior of Epoxides towards [3+2]‐Annulation Reactions with Donor‐Acceptor Cyclopropanes: Synthesis of Substituted Cyclopentane and Tetrahydrofuran. Issue 12 (31st March 2017)

• Record Type: Journal Article
• Authors: Pandey, Ashok Kumar; Varshnaya, Rohit Kumar; Banerjee, Prabal
• Is Part Of: European journal of organic chemistry. Issue 12(2017)
• Page Start: 1647
• Page End: 1656
• Publication Date: 2017-03-31
• Subjects: Synthetic methods -- Oxygen heterocycles -- Epoxides -- Enols -- Annulation; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201601549
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : Substituent and Lewis acid promoted generation of functionalized enolates from epoxides is developed. Divergent attack of the enolate on donor‐acceptor cyclopropanes, i.e. C ‐attack or O ‐attack depending upon substituents present in both reacting partners, produced different products. C ‐attack gave functionalized cyclopentane derivatives, whereas O ‐attack furnished tetrahydrofuran derivatives through [3+2]‐annulation reactions. Moreover, to increase the utility of our method, synthesized diastereomeric cyclopentane derivatives were converted into synthetically useful cyclopentene and cyclopentanone analogs. Abstract : Lewis acid catalyzed in situ generation of enolate from epoxide is developed. C‐attack or O‐attack of the substituted enolate on donor‐acceptor cyclopropane gave functionalized cyclopentane and tetrahydrofuran through a formal [3+2]‐annulation reaction. Further transformation of cyclopentane into synthetically important cyclopentanone and cyclopentene is also achieved.