Chemo- and regioselective crossed alkyne cyclotrimerisation of 1,6-diynes with terminal monoalkynes mediated by Grubbs’ catalyst or Wilkinson’s catalystElectronic supplementary information (ESI) available: experimental procedures and analytical data for 3, 4 and 5. See http://www.rsc.org/suppdata/cc/b0/b005636g/

Abstract

A novel protocol for crossed alkyne cyclotrimerisations mediated by Grubbs’ catalyst [RuCl₂(CHPh)(PCy₃)₂] allows the efficient synthesis of 4,6-substituted indolines with high regioselectivity, and it is complementary to alkyne cyclotrimerisations mediated by Wilkinson’s catalyst [RhCl(PPh₃)₃] allowing the regioselective synthesis of the corresponding 4,5-substituted isomers in many cases.