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