Expanding the Scope of Primary Amine Catalysis: Stereoselective Synthesis of Indanedione-Fused 2,6-Disubstituted trans-Spirocyclohexanones

G. Madhusudhan Reddy, Chi Ting Ko, Kai Hong Hsieh, Chia Jui Lee, Utpal Das, Wenwei Lin

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

A cinchona-alkaloid-derived chiral primary-amine-catalyzed enantioselective method for the synthesis of the thermodynamically less stable indanedione-fused 2,6-trans-disubstituted spirocyclohexanones is demonstrated. Both the enantiomeric forms of the trans isomer are obtained in excellent yields and enantioselectivities. Furthermore, one of the enantiopure trans-spiranes bearing an additional α-substitution on the cyclohexanone ring was then epimerized into its thermodynamically stable cis counterpart, with little loss of enantioselectivity to demonstrate the feasibility of such a transformation. Mechanistic investigations revealed two competing pathways, a concerted Diels-Alder reaction and a stepwise Michael addition, for the formation of corresponding products.

Original languageEnglish
Pages (from-to)2420-2431
Number of pages12
JournalJournal of Organic Chemistry
Volume81
Issue number6
DOIs
Publication statusPublished - 2016 Mar 18

ASJC Scopus subject areas

  • Organic Chemistry

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