Kinetic resolution of activated nitroallylic acetates with aldehydes and ketones through a conjugate addition-elimination S N2′ process

Raju Jannapu Reddy, Pei Hsun Lee, Dhananjay R. Magar, Jung Hsuan Chen, Kwunmin Chen

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A unique organocatalytic kinetic resolution (KR) of nitroallylic acetates has been developed. A variety of racemic nitroallylic acetates (1a-n) were resolved with chiral enamines formed in situ from the reaction of aldehydes and ketones with organocatalyst 2b (2.5 mol-%) and 14c (20 mol-%), respectively, through an interesting S N2′ reaction. The densely functionalized products 3-5 were obtained with high to excellent levels of stereoselectivities (up to >99:1 dr and >99%) in good to high chemical yields. The unreactive starting substrates 1a-n were recovered with good to high optical purity (up to 98%). The scope and generality of the kinetic resolution was expanded to include a wide range of nitroallylic acetates with various aldehydes and ketones as the donor sources. The absolute stereochemistry of the functionalized products and the unreacted substrate were determined. Synthetic application was demonstrated when (S)-citronellal was treated with rac-1a in the presence of 2b to give 12 as a single diastereomer, which was further cyclized to give a tetrasubstituted cyclohexane derivative 13 with excellent stereoselectivity. Transition-state models were proposed to account for the stereochemical bias in the KR process.

Original languageEnglish
Pages (from-to)353-365
Number of pages13
JournalEuropean Journal of Organic Chemistry
Issue number2
DOIs
Publication statusPublished - 2012 Jan 1

Fingerprint

Ketones
aldehydes
Aldehydes
ketones
Stereoselectivity
acetates
elimination
Acetates
Kinetics
kinetics
Stereochemistry
stereochemistry
Substrates
products
cyclohexane
purity
Derivatives

Keywords

  • Aldehydes
  • Diastereoselectivity
  • Enantioselectivity
  • Ketones
  • Kinetic resolution
  • Organocatalysis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

Cite this

Kinetic resolution of activated nitroallylic acetates with aldehydes and ketones through a conjugate addition-elimination S N2′ process. / Jannapu Reddy, Raju; Lee, Pei Hsun; Magar, Dhananjay R.; Chen, Jung Hsuan; Chen, Kwunmin.

In: European Journal of Organic Chemistry, No. 2, 01.01.2012, p. 353-365.

Research output: Contribution to journalArticle

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