First synthesis of ferrocenyl-substituted thiochalcones and their [4+2]-cycloadditions with acetylenic dienophiles.

Ferrocenyl methyl ketone reacts with aromatic aldehydes yielding 1-ferrocenyl-3-aryl-propenones (chalcones), which upon treatment with Lawesson’s reagent (LR) are converted to the corresponding thiochalcones. The latter enter the thia-Diels-Alder reaction with acetylenic dienophiles (DMAD and methyl propiolate) to give ferrocenyl-substituted 4<italic>H</italic>-thiopyrans. In the case of methyl propiolate, the formation of the six-membered ring occurs with complete regioselectivity. [ABSTRACT FROM AUTHOR]