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