New cyclic chiral nitrones constituting two diastereomers were synthesized by the reaction of isonitroso Meldrum's acid with l-menthone via a nitrosoketene intermediate. Both nitrones reacted with allyltrimethylsilane diastereoselectively to give the corresponding isoxazolidine derivatives as sole products, which converted to (S)- and (R)-allylglycines in ca. 100% ee, respectively.