Transition metal catalysed synthesis of tetrahydro derivatives of [5]-, [6]- and [7]helicene

Abstract

Tetrahydro analogues of [5]-, [6]- and [7]helicene have been easily prepared by intramolecular [2+2+2] cycloisomerization of appropriate triynes under CpCo(CO)(2)/PPh3 or Ni(cod)(2)/PPh3 catalysis.