Scheme 3 illustrates {TAIL ~ a method} of synthesizing the R and S enantiomers of the starting materials of the formula VII wherein {HEAD ~ X} is sulfur 
Scheme 3 illustrates { TAIL ~ a method } of synthesizing the R and S enantiomers of the starting materials of the formula VII wherein { HEAD ~ X } is sulfur
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH