The mixed coupling of XV and XVI constitutes an entirely similar, if less striking, example. Such behavior of two components in a mixed Ullmann reaction bears some formal resemblance to certain copolymerization phenomena, in which monomer A may polymerize much more rapidly with monomer B than the latter does with itself in the monomer mixture, and yet A may be very sluggish in selfpolymerization. Inasmuch as copolymerization ...
