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