Catalytic asymmetric 1,3-dipolar cycloaddition of two different ylides: facile access to chiral 1,2,4-triazinane frameworks.

Ylides at a crossing: An unprecedented 1,3-dipolar cycloaddition (cross-cycloaddition) between two different ylides was realized by using the chiral Cu(I) /tBu-Phosferrox complex as the catalyst under mild reaction conditions. This catalytic system provides an expeditious approach to the construction of highly functionalized 1,2,4-triazinane derivatives in good yields with excellent diastereoselectivities and enantioselectivities.