ClTi(OiPr)3-promoted reductive amination on the solid phase: combinatorial synthesis of a biaryl-based sulfonamide library.

A combinatorial library (9 amines x 7 sulfonyl chlorides x 13 boronic acids = 819 compounds) was produced on solid support in a four-step sequence, i.e., ClTi(O(i)Pr)3-promoted reductive amination, sulfonylation of the resin-bound amine, Suzuki cross-coupling, and acid-mediated cleavage. The library members were obtained in moderate quantity (1-8 mg) with over 70% of the sampled products greater than 90% pure according to LC-MS analysis.