Two configurational isomers of bis-urea macrocycles have been synthesized, and their neutral molecule recognition was studied by X-ray crystallography and ¹H NMR experiments. Cooperative action between the deep cavity and the urea groups and the influence of dipole alignments on molecular recognition are discussed.

A novel asymmetric ring-opening reaction of N-substituted azabenzonorbornadienes with a wide variety of substituted benzyl alcohols and the addition reaction of N-substituted azabenzonorbornadienes with thiols are reported, affording the corresponding 1,2-trans-alkoxyamino products in moderate yields with excellent enantioselectivities (up to 94% ee) and the corresponding thiol addition products in high yields with lower enantiomeric excesses (ee) in the presence of iridium catalyst, respectively. The effects of ligands, catalyst loading, solvents and additives, and temperature were also investigated. The anti-configuration of the product 3c was confirmed by X-ray crystal structure analysis. A possible mechanism for the present catalytic reaction is proposed.

A new 1,3-dipolar cycloaddition of oxa(aza)bicyclic alkenes with nitrones has been developed. The operationally simple cycloaddition allows efficient synthesis of fused bicyclic tetrahydroisoxazoles bearing exo- and anti-five member heterocyclic rings (76–99% yields) without any catalyst and additive under mild conditions. The proposed concerted mechanism and the observed selectivity are investigated by DFT calculations of the reaction pathways. This mild and practical [3 + 2] cycloaddition provides an efficient route to access highly functionalized compounds.