Chiral dihydroxy thioethers derived from L-mandelic and L-lactic acid are a
ctivated with SOCl2, SOBr2 and by bis-trifluoroacetate formation to give op
tically active mustard gas analogues. These compounds serve as substrates f
or stereospecific nucleophilic substitution reactions with NaSEt and NaSPh
to furnish C-2-symmetric tris-thioethers with overall inversion of configur
ation. (C) 2001 Elsevier Science Ltd. All rights reserved.