Regiocontrolled syntheses of some new spiro[polycyclic-1′-isothiochroman]-4′-one derivatives

Indan-1-one (1a), 1-tetralone (1b), fluorenone (1c), and anthrone (1d) reacted with mercaptoacetic acid in toluene in the presence of p-toluenesulfonic acid to give spiro[indan-1,2′-[1′,3′]oxathialan]-5′-one (2a), spiro[tetrahydro-naphthalene-1,2′-[1,3′]oxathialan]-5′-one (2b), spiro[fluorene9,2′-[1′,3′]-oxathialan]-5′-one (2c), and spiro[anthracene-9(10H)-2′-[1′,3′]-oxathialan]-5′-one (2d), respectively. Compounds 2a–d reacted with arenes in the presence of aluminum chloride to yield spiro[polycyclic-1′-isothiochroman]-4′-one derivatives 3a–t. The mechanisms of these reactions are discussed. All the synthesized spiroheterocycle derivatives were identified by conventional methods (IR, ¹H-NMR spectroscopy) and elemental analyses. © 1996 John Wiley & Sons, Inc.