Throughout this paper, a compound numbering system common for combinatorial chemistry has been used. Thus, heterocyclic substrates, carboxylic acids, and trifluoroborates for the library synthesis were labeled as 1{i}, 2{j}, and 3{j}, respectively, where i and j are positive integer numbers starting with 1. The library members synthesized from reagents 1{i} and 2{j}/3{j} were designated as 4{i,j}.