Diastereoselective reactions of 1,1,1-trichloro(trifluoro)-3-nitrobut-2-enes with 2-morpholinoalk-1-enes

Reactions of (E)-1,1,1-trichloro(trifluoro)-3-nitrobut-2-enes with 3,3-dimethyl-2-morpholinobutene in benzene give (4R*,6R*)-6-tert-butyl-3-methyl-6-morpholino-4-trihalomethyl-5,6-dihydro-4H-1,2-oxazine 2-oxides. In a dichloromethane solution, these cyclic nitronates undergo diastereoselective ring opening to produce nitroalkylated anti-CCl₃- and syn-CF3-enamines, which are hydrolysed with dilute HCl to afford the respective anti-CCl₃- and syn-CF3-g-nitroketones.