Core scaffold-inspired stereoselective synthesis of spiropyrazolones via an organocatalytic Michael/cyclization sequence

J Org Chem. 2012 Nov 16;77(22):10228-34. doi: 10.1021/jo301851a. Epub 2012 Oct 30.

Abstract

Herein, the organocatalytic asymmetric Michael/cyclization sequence of α-isothiocyanato imides and esters with a variety of unsaturated pyrazolones is presented, in general, affording functionalized spiropyrazolones containing three contiguous stereogenic centers in high levels of diastereo- and enantioselectivity (up to 20:1 dr and 99% ee). Moreover, the current protocol provides a highly efficient and convenient strategy that allows rapid enantioselective construction of diversely spiropyrazolone skeletons with high optical purity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Crystallography, X-Ray
  • Cyclization
  • Molecular Structure
  • Pyrazolones / chemical synthesis*
  • Pyrazolones / chemistry
  • Spiro Compounds / chemical synthesis*
  • Spiro Compounds / chemistry*
  • Stereoisomerism

Substances

  • Pyrazolones
  • Spiro Compounds