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