In more detail, {TAIL ~ a compound} having {HEAD ~ an S configuration} selectively produces a compound having an S—R configuration, and a compound having an R configuration selectively produces a compound having an R—S configuration 
In more detail , { TAIL ~ a compound } having { HEAD ~ an S configuration } selectively produces a compound having an S — R configuration , and a compound having an R configuration selectively produces a compound having an R — S configuration
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH