Sulphinylcarboxylic acids

Addition of the dianion of /5-sulphinylcarboxylic acids to carbonyl compounds leads to the formation of the corresponding hydroxy derivatives which undergo spontaneous cyclization to give y-lactones440. Bravo and coworkers have found that when optically active ( + )-(R)-3-(p-toluenesulphinyl)propionic acid 426 is used for this reaction, the corresponding diastereoisomeric / -sulphinyl-y-lactones 427 are formed in a ratio which is dependent on the substituents in the carbonyl component441,502 503 (equation 256). 

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