Synthesis of 3,4-Dihydro-2H-Pyran derivatives Utilizing Ag₂CO₃/Celite

Ag₂CO₃/Celite를 이용한 3,4-다이하이드로-2H-피란 유도체들의 합성

An efficient synthesis of 3,4-dihydro-2H-pyrans is achieved by $Ag_2CO_3$/celite mediated reaction of 1,3-dicarbonyl compounds with vinyl ether in moderate yields. This method has been applied to the synthesis of 3,4-dihydro-2H-pyranochromens and 3,4-dihydro-2H-benzochromen. 3,4-Dihydro-2H-pyranochromens were easily converted to 4H-pyranochromens by elimination of ethoxy group. The structures of these compound were identified by IR and $^1H$ NMR-Spectra.