Sulphoxides. Part II. Stereochemistry of the γ-disulphoxides 2,5-di-thiahexane 2,5-dioxide and 1,4-diphenyl-1,4-dithiabutane 1,4-dioxide

Abstract

‘Andersen’-type synthesis of 2,5-dithiahexane 2,5-dioxide (1) and 1,4-diphenyl-1,4-dithiabutane 1,4-dioxide (2), from di-(–)-menthyl ethane-1,2-disulphinate (3) and the appropriate Grignard reagents, yielded higher melting (or α-)meso-(1) and meso-(2) and optically active lower melting (β-)(1) and (2). The absolute rotation of compound (1) was determined by the isotopic dilution method (and found to be extremely high), the ¹H n.m.r. spectra of optically active (1) in (–)-2,2,2-trifluoro-1 -phenylethanol not being decisive for the determination of its optical purity.