Synthesis of substituted chiral chromans via organocatalytic kinetic resolution of racemic 3-nitro-2-aryl-2H-chromenes with ketones catalyzed by pyrrolidinyl-camphor-derived organocatalysts

Dhananjay R. Magar, Kwunmin Chen

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Efficient kinetic resolution of racemic 2-aryl-3-nitro-2H-chromenes (1a-l) has been explored with the pyrrolidinyl-camphor derivative 2b as a bifunctional organocatalyst under neat conditions in the presence of AcOH at 0 °C. In general, the organocatalytic asymmetric Michael addition of ketones proceeded smoothly to give the functionalized Michael adducts (3a-n) with good-to-high diastereo- and enantioselectivities (up to 92:8 dr, 93% ee, and 47% yield). The less reactive chromenes (S)-1a-h, k, l and (R)-1i-j were recovered in high chemical yields and moderate optical purity (up to 42% chemical yield and 72% ee).

Original languageEnglish
Pages (from-to)5810-5816
Number of pages7
JournalTetrahedron
Volume68
Issue number29
DOIs
Publication statusPublished - 2012 Jul 22

Fingerprint

Chromans
Benzopyrans
Camphor
Ketones
Kinetics
Enantioselectivity
Derivatives
5,7-dimethoxy-2-methyl-2H-benzopyran

Keywords

  • Chromans
  • Chromenes
  • Kinetic resolution
  • Michael addition
  • Organocatalysis

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Cite this

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title = "Synthesis of substituted chiral chromans via organocatalytic kinetic resolution of racemic 3-nitro-2-aryl-2H-chromenes with ketones catalyzed by pyrrolidinyl-camphor-derived organocatalysts",
abstract = "Efficient kinetic resolution of racemic 2-aryl-3-nitro-2H-chromenes (1a-l) has been explored with the pyrrolidinyl-camphor derivative 2b as a bifunctional organocatalyst under neat conditions in the presence of AcOH at 0 °C. In general, the organocatalytic asymmetric Michael addition of ketones proceeded smoothly to give the functionalized Michael adducts (3a-n) with good-to-high diastereo- and enantioselectivities (up to 92:8 dr, 93{\%} ee, and 47{\%} yield). The less reactive chromenes (S)-1a-h, k, l and (R)-1i-j were recovered in high chemical yields and moderate optical purity (up to 42{\%} chemical yield and 72{\%} ee).",
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AU - Magar, Dhananjay R.

AU - Chen, Kwunmin

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N2 - Efficient kinetic resolution of racemic 2-aryl-3-nitro-2H-chromenes (1a-l) has been explored with the pyrrolidinyl-camphor derivative 2b as a bifunctional organocatalyst under neat conditions in the presence of AcOH at 0 °C. In general, the organocatalytic asymmetric Michael addition of ketones proceeded smoothly to give the functionalized Michael adducts (3a-n) with good-to-high diastereo- and enantioselectivities (up to 92:8 dr, 93% ee, and 47% yield). The less reactive chromenes (S)-1a-h, k, l and (R)-1i-j were recovered in high chemical yields and moderate optical purity (up to 42% chemical yield and 72% ee).

AB - Efficient kinetic resolution of racemic 2-aryl-3-nitro-2H-chromenes (1a-l) has been explored with the pyrrolidinyl-camphor derivative 2b as a bifunctional organocatalyst under neat conditions in the presence of AcOH at 0 °C. In general, the organocatalytic asymmetric Michael addition of ketones proceeded smoothly to give the functionalized Michael adducts (3a-n) with good-to-high diastereo- and enantioselectivities (up to 92:8 dr, 93% ee, and 47% yield). The less reactive chromenes (S)-1a-h, k, l and (R)-1i-j were recovered in high chemical yields and moderate optical purity (up to 42% chemical yield and 72% ee).

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