5S)-2,2-dimethyl-4-phenyl-1,3-dioxan-5-ylamine (1), were heated with a variety of aromatic aldehydes in chlorobenzene under reflux. The in situ generated 1,3-dipols were trapped with fumaric acid ester, fumaric acid nitrile or N-phenylmaleimide, respectively, that were present in excess in the reaction mixture. The cycloadducts 4a-e, 5a-f were formed in 78–91% and 67–100% yield as mixture of exolendo-isomers