Facile strategy for the preparation of pyrazoline derivatives through phosphine-promoted [2 + 3] cycloaddition of dialkyl azodicarboxylates with β,γ-unsaturated α-keto esters

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

KEYWORDS:

• β,γ-Unsaturated α-keto esters
• cycloaddition
• dialkyl azodicarboxylates
• Ph₃P

Additional information

Funding

The Project of Science and Technology of the Department of Education, Anhui Province (No. KJ2017B005), and Youth Project of Huaibei Normal University (2014xq016).