Keto-sulphoxides and Related Compounds

P-Keto-sulphoxides and Related Compounds.—Standard syntheses have been illustrated in the recent literature methyl benzenesulphinate reacts with an active methylene compound in the presence of NaH to give a j8-keto-sulphoxide, and preparations from cyanohydrins have been described. pKa, Values of a series of substituted a-phenylsulphinylacetophenones are readily correlated with Hammett -values.  

New uses for j8-keto-sulphoxides in synthesis are a one-step conversion into a-acetoxy-thiolesters with AC2O and NaOAc [PhC(0)CH2S(0)Ar - PhCH(OAc)-C(0)SAr], conversion of a 2-phenylsulphinylcyclohexanone into a 2-phenyl-thiocyclohex-2-en-l-one (Pummerer rearrangement), and the acid-catalysed cyclization of j8-keto-sulphoxides of general structure ArCHR CHR C(0)- 

Kunieda, Y. Fujiwara, J. Nokami, and M. Kinoshita, Bull. Chem. Soc. Japan, 1976, 49, 575. 

CHR S(0)Me to give 2-methylthio-3-oxo-tetrahydronaphthalenes. Synthesis of a heterocyclic analogue starting from the corresponding pyrrole has been reported. Synthesis of a known intermediate for use in an oestrone synthesis starts from the homologue (51), which is subja ted to thermal elimination in the presence of 2-methylcyclopentane-l,3-dione.  

A crystalline, thermally stable, jS-sultine is obtained by cyclization of the jS-hydroxy-sulphoxide Ph2C(0H)CMe2S(0)Bu with SO2CI2, confirming and developing an earlier observation.  

---