Stereoselective synthesis of densely functionalized pyrrolidin-2-ones by a conjugate addition/nitro-Mannich/lactamization reaction

J Org Chem. 2012 Jul 20;77(14):6186-98. doi: 10.1021/jo301000r. Epub 2012 Jun 28.

Abstract

Copper-catalyzed conjugate addition of diorgano zinc reagents to nitroacrylate 1 followed by a subsequent nitro-Mannich reaction and in situ lactamization leads to an efficient one-pot synthesis of 1,3,5-trisubstituted 4-nitropyrrolidin-2-ones (5). The versatility of the reaction is shown for a wide range of N-p-(methoxy)phenyl protected aldimines 3 derived from alkyl, aryl, and heteroaryl aldehydes. The densely functionalized pyrrolidin-2-ones 5 are isolated as single diastereoisomers (40 examples, 33-84% yield). An enantioselective copper-catalyzed conjugate addition of diethylzinc led to highly crystalline products that could be recrystallized to enantiopurity in high yield. A range of successful chemoselective transformations were investigated, which widens the applicability of the pyrrolidn-2-ones as stereochemically pure building blocks for further organic synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Copper / chemistry
  • Molecular Structure
  • Nitro Compounds / chemistry
  • Organometallic Compounds / chemistry
  • Pyrrolidinones / chemical synthesis*
  • Pyrrolidinones / chemistry
  • Stereoisomerism
  • Zinc / chemistry

Substances

  • Nitro Compounds
  • Organometallic Compounds
  • Pyrrolidinones
  • Copper
  • Zinc