The process employing a non chiral auxiliary in the starting material can employ either a fluoride ion catalyst or a salt of {HEAD ~ a chiral or non chiral auxiliary} for {TAIL ~ cyclization} 
for
The process employing a non chiral auxiliary in the starting material can employ either a fluoride ion catalyst or a salt of { HEAD ~ a chiral or non chiral auxiliary } for { TAIL ~ cyclization }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL