Phenylsulfinylacetic acid

We begin with studies of the pKa values of substituted phenylmercapto-, phenylsulfinyl-and phenylsulfonyl-acetic acids. Pasto and Kent136 found that phenylsulfinylacetic acid was a weaker acid than phenylsulfonylacetic acid in water, the pKa values at 25 °C being 2.732 and 2.513 respectively. However, in aqueous ethanol or aqueous dioxan as solvent... 

The stereoreactivity of the methylene protons of er -butyl (4-methylphenylsulfinyl)acetate is in sharp contrast with the highly stereospecific behavior of the methylene protons of benzyl methyl sulfoxide. An NMR study of phenylsulfinylacetic acid showed that the reactivity of these two diastereotopic protons is comparable83. These protons are even magnetically equivalent in deuterium oxide solution. The diastereoselectivity of the alkylation of a-sulfinyl carboxylic esters is poor, moreover, the reaction proceeds only when butyllithium, ferz-butyllithium or lithium diethylamide is used as the base in the preparation of the carbanion82. 

The condensation of aromatic and aliphatic aldehydes with sulfoxide-activated methylenes like phenylsulfinylacetonitriles and phenylsulfinylacetates selectively forms a-sulfinyl-a,3-unsaturated carbonyl compounds (144) with the alkyl or aryl group trans to the sulfinyl group (see Section 1.11.2.5).52-73-186,187 Oxidations of (144) with m-chloroperbenzoic acid yield the unsaturated (E)-sulfones... 

METHYL KETONES Chromic acid. Ethyl a-phenylsulfinylacetate. Lithium acetylide. Lithium diethylamide-Hexamethylphophoric triamide. S-(2-Methoxyallyl)-N,N-dimeth-yldithiocarbamate. a-Methoxyvinyllithium. Phenylthioacetjc add. Potassium tetra-carbonylhydridoferrate. Silver(II) oxide. Trimethylaluminium. 

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