Synthesis of New Isoxazolidine Derivatives Utilizing the Functionality of <i>N</i>-Carbonylpyrazol-Linked Isoxazolidines

Abstract

Using Ni(II) as the catalyst, electron-deficient 3,5-dimethylacryloylpyrazole olefin was reacted with C,N-diarylnitrones alone for 10 min to prepare novel five-member heterocyclic products, 4-3,5-dimethylacryloylpyrazole isoxazolidines with 100% regioselectivity and up to 99% yield. And then, taking these cycloadducts as substrates, six kinds of derivatization reactions, like ring-opening, nucleophilic substitution, addition-elimination and reduction, were studied. Experimental results showed that all kinds of transformations could obtain the target products at a high conversion rate under mild conditions, a finding which provided the basic methods for organic synthesis methodology research based on an isoxazolidine skeleton.

Keywords

• 3,5-dimethylpyrazole
• isoxazolidine
• 1,3-dipolar cycloaddition
• nucleophilic substitution
• reduction reaction