[5C + 1S] annulation: A facile and efficient synthetic route toward functionalized 2,3-dihydrothiopyran-4-ones

A facile and efficient synthetic route toward highly substituted 2,3-dihydrothiopyran-4-ones was developed through a formal [5C + 1S] annulation of readily available alpha-alkenoyl ketene-(S,S)-acetals with sodium sulfide nonahydrated salt (Na(sub 2)S.9H(sub 2)O) and utilized in the synthesis of 2-(4-chlorophenyl)-6-(morpholin-4-yl)-4H-thiopyran-4-one, an inhibitor of DNA-dependent protein kinase (DNA-PK).