Preferred template and scaffold structures also include those that are capable of reacting with {HEAD ~ reagents} without {TAIL ~ the need} for a catalyst 
without
Preferred template and scaffold structures also include those that are capable of reacting with { HEAD ~ reagents } without { TAIL ~ the need } for a catalyst
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH