2‐Aryl‐2‐[1‐(2‐hydroxypropyl)]‐1,3‐dithianes as Versatile Building Blocks for the Preparation of Enantiomerically Pure Drugs

An efficient access to chiral, non racemic arylbutanols 1a–c (ee>98%) as drug intermediates is described. Thioacetalization of substituted benzaldehydes 3a–c with 1,3‐propanedithiol gave 2‐aryl‐1,3‐dithianes 4a–c. Lithiation of 4a–c followed by reaction with racemic, (R)‐ or (S)‐propylene oxide, respectively, gave racemic, (R)‐ or (S)‐hydroxyalkyldithianes 5a–c in high yields. Subsequent desulfurization with tributyltin hydride (TBTH) resulted in almost quantitative formation of the arylbutanols 1a–c. Ketols 6 were obtained by hydrolysis of the hydroxyalkyldithianes 5a.