Selective 1,2-dihalogenation and oxy-1,1-dihalogenation of alkynes by N-halosuccinimides

1,2-Dihalogenation and oxy-1,1-dihalogenation of alkynes by N-halosuccinimides can be selectively realized through using different reaction conditions. alpha,beta-Dihalo alkenes were obtained exclusively using THF as solvent without using any catalyst, while alpha,alpha-dihalo ketones were synthesized using a mixed solvent of THF and H2O in the presence of FeCl3 center dot 6H(2)O. Terminal aromatic alkynes are smoothly transformed into alpha,alpha-dihalo ketones on water without a catalyst. (C) 2011 Elsevier Ltd. All rights reserved.