An Ultimate Stereocontrol in Asymmetric Synthesis of Optically Pure Fully Aromatic Helicenes

J Am Chem Soc. 2015 Jul 8;137(26):8469-74. doi: 10.1021/jacs.5b02794. Epub 2015 May 18.

Abstract

The role of the helicity of small molecules in enantioselective catalysis, molecular recognition, self-assembly, material science, biology, and nanoscience is much less understood than that of point-, axial-, or planar-chiral molecules. To uncover the envisaged potential of helically chiral polyaromatics represented by iconic helicenes, their availability in an optically pure form through asymmetric synthesis is urgently needed. We provide a solution to this problem present since the birth of helicene chemistry in 1956 by developing a general synthetic methodology for the preparation of uniformly enantiopure fully aromatic [5]-, [6]-, and [7]helicenes and their functionalized derivatives. [2 + 2 + 2] Cycloisomerization of chiral triynes combined with asymmetric transformation of the first kind (ultimately controlled by the 1,3-allylic-type strain) is central to this endeavor. The point-to-helical chirality transfer utilizing a traceless chiral auxiliary features a remarkable resistance to diverse structural perturbations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alcohols / chemistry
  • Catalysis
  • Chemistry, Organic / methods*
  • Kinetics
  • Lipase / chemistry
  • Models, Chemical
  • Models, Molecular
  • Molecular Structure
  • Optics and Photonics
  • Polycyclic Compounds / chemistry*
  • Stereoisomerism

Substances

  • Alcohols
  • Polycyclic Compounds
  • helicenes
  • Lipase