A one-pot, two step synthesis of 2,2-disubstituted 1-nitroalkenes

Abstract

The reactions of ketones 1a– o , nitromethane 2 , and a stoichiometric amount of piperidine 3a or ethylenediamine 3b in the presence of mercaptan 6a in THF or CH 3CN solution give high yields of β-nitrosulfides 7a– o . The latter can be oxidized by 8a ( m-CPBA or m-CPBA/AcOH) at 0°C, 8b (H 2O 2/AcOH), or 8c (H 2O 2) at room temperature, thus generating β-nitroalkylsulfoxides 9a– o , which then undergo elimination to produce medium to high yields of 2,2-disubstituted-1-nitroalkenes 5a– o , when refluxed in a solution of ClCH 2CH 2Cl (1,2-dichloroethane). After preparation from 1a– o , 2 , 3 , and 6a , 7a– o were oxidized with 8a, 8b , or 8c in a mixture of CH 3CN and ClCH 2CH 2Cl to generate β-nitrosulfoxides 9a– o , which then underwent elimination under refluxing under one-pot conditions. Compounds 14 and 15g were also prepared using 13 , 2 , 3b , and 6 , in a similar manner.