1 School of Chemistry and Environmental Science, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Henan 453007, P. R. China.
A highly efficient synthesis of diversely substituted 2H-pyran-2-ones and indenes through Brønsted acid promoted tandem reaction of the readily obtainable 3-hydroxyhexa-4,5-allenic esters under extremely mild conditions has been developed.