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