A Convenient Preparative Method of Nitrile Oxides by the Dehydration of Primary Nitro Compounds with Ethyl Chloroformate or Benzenesulfonyl Chloride in the Presence of Triethylamine

Three nitrile oxides (MeOCOC≡N→O, PhC≡N→O, and EtC≡N→O) were effectively generated in situ by dehydration of the corresponding primary nitro compounds (RCH2NO2) with PhSO2Cl or ClCOOEt in the presence of triethylamine. Various cycloadducts were prepared by the reaction of them with dipolarophiles. Some advantages of these methods are described in comparison with other known methods.