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