Organocatalytic aryl-aryl bond formation: an atroposelective [3,3]-rearrangement approach to BINAM derivatives

J Am Chem Soc. 2013 May 22;135(20):7414-7. doi: 10.1021/ja401709k. Epub 2013 May 9.

Abstract

Herein we disclose an organocatalytic aryl-aryl bond-forming process for the regio- and atroposelective synthesis of 2,2'-diamino-1,1'-binaphthalenes (BINAMs). In the presence of catalytic amounts of axially chiral phosphoric acids, achiral N,N'-binaphthyl hydrazines undergo a facile [3,3]-sigmatropic rearrangement to afford enantiomerically enriched BINAM derivatives in good to excellent yield. This transformation represents the first example of a metal-free, catalytic C(sp(2))-C(sp(2)) bond formation between two aromatic rings with concomitant de novo atroposelective installation of an axis of chirality. Density functional calculations reveal that, in the transition state for C-C bond formation, the phosphoric acid proton of the catalyst is fully transferred to one of the N-atoms of the substrate, and the resulting phosphate acts as a chiral counterion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Hydrazines / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Naphthalenes / chemical synthesis*
  • Naphthalenes / chemistry
  • Phosphoric Acids / chemistry*

Substances

  • 2,2'-diamino-1,1'-binaphthalene
  • Hydrazines
  • Naphthalenes
  • Phosphoric Acids