ABSTRACT
A facile phosphine-promoted [2 + 3] cycloaddition of dialkyl azodicarboxylates with β,γ-unsaturated α-keto esters was developed, and a series of pyrazoline derivatives were obtained with good yields under mild conditions. Furthermore, the scope of the cyclizations was investigated.
GRAPHICAL ABSTRACT
![](/cms/asset/d1768ba8-f32d-4e6f-b463-d9f1e9451173/lsyc_a_1435819_uf0001_b.png)