Description General description Ethyl 2,3-butadienoate is an α-allenic ester. The reaction of ethyl 2,3-butadienoate with N-tosylated imines in the presence of DABCO (1,4-diazabicyclo[2.2.2]octane) or DMAP (4-dimethylaminopyridine) forms azetidine derivatives or novel dihydropyridine derivatives respectively. The performance of bifunctional N-acyl aminophosphines to catalyze the asymmetric [3+2] cycloaddition of phenylidenemalononitrile with ethyl 2,3-butadienoate has been evaluated. Application Ethyl 2,3-butadienoate may be used in the synthesis of dihydropyrans by reacting with acyclic enones. It may also be used to synthesize spiranic heterocycles by reacting with heterocyclic bis-arylidene ketones via phosphine-catalyzed [3+2] annulations. Packaging 1, 5 g in glass bottle