This in turn is then ring closed by a stereospecific process of inversion with {HEAD ~ pyridine} in {TAIL ~ p toluenesulfonyl chloride} to obtain dibenzofuran 
in
This in turn is then ring closed by a stereospecific process of inversion with { HEAD ~ pyridine } in { TAIL ~ p toluenesulfonyl chloride } to obtain dibenzofuran
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 TAIL OTH OTH OTH