An efficient synthesis of monoarylidene derivatives of pyran-4-one and piperidin-4-one

A room-temperature procedure is developed for the direct synthesis of monoarylidene derivatives of pyran-4-one and piperidin-4-one systems under solventfree conditions. Relatively high yields of products are obtained from the reaction of ketones 1 with different aromatic and aliphatic aldehydes under the catalytic system of TMSNMe2 and MgBr2.OEt2. Notably, formation of the undesired bis counterparts, as a major limitation of these reaction types, is minimized using the employed conditions.