A new application of Baylis–Hillman alcohols to a diastereoselective synthesis of 3-nitrothietanes

Three key reactions, the generation of a nucleophile, an thia-Michael addition and an intramolecular cyclisation, were used to achieve an efficient one-pot diastereoseletive synthesis of 3-nitrothietanes. Thus, Baylis–Hillman alcohols and their aldehydes were reacted with either O,O-diethyl hydrogen phosphorodithioate or O,O-diethyl hydrogen phosphorodithioate in combination with a task-specific ionic liquid [bmim]X–Y to afford the corresponding 2,3-di- or 2,3,4-trisubstituted thietanes, respectively. The reaction is high yielding and proceeds with complete diastereoselectivity in favour of the trans isomers.