Nitroketene dithioacetal chemistry: Synthesis of 2-alkylthio-3-nitrothiophenes from nitroketene dithioacetate and chloromethyl ketones.

An effective synthesis of highly functionalized 3-nitrothiophenes was achieved from the reaction of simple, inexpensive, and readily available dipotassium 2-nitro-1,1-ethylyenedithiolate with alpha-chloromethyl ketones in toluene catalyzed by tetrabutylammonium bromide (TBAB). Thiophene formation is highly sensitive and selective for chlorine, present as a leaving group in alpha-chloromethyl ketones.