Careful attention must be paid to step wherein {HEAD ~ the trimethylsilylating agent} is added to {TAIL ~ the molten alcohol}, catalyzed with the organic superacid, to avoid an uncontrollable reaction 
is added to
Careful attention must be paid to step wherein { HEAD ~ the trimethylsilylating agent } is added to { TAIL ~ the molten alcohol } , catalyzed with the organic superacid , to avoid an uncontrollable reaction
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH