New chemical access for pyran core embedded derivatives from bisalkenylated 1,3-diketones and 1,3-diketoesters via tandem C-dealkenylation and cyclization

New chemical access has been developed for the synthesis of pyran core embedded derivatives from 1,3-diketones and 1,3-diketoesters, in which the active methylene group of 1,3-diketone or 1,3-diketoester was alkenylated with three equivalents of alkenyl bromides in presence NaH to give bisalkenyl 1,3-diketones or 1,3-diketoesters and the resultant bisalkenyl 1,3-diketones or 1,3-diketoesters were reacted with AlCl3 at room temperature to furnish pyran core embedded derivatives in good to excellent yields.