The boronic Mannich reaction in a solid-phase approach

We report herein the use of the multi-component boronic Mannich reaction (B MR) in a solid-phase approach, in which an aryl boronic acid is combined wi th an aldehyde and a secondary amine. We describe several examples, in whic h each of the three components is alternately anchored onto Wang polystyren e, giving in most cases (but not all) the expected products in high yields and purities. We also suggest, based on B-11 NMR studies, that the intermed iate formation of a tetracoordinated boron species could represent the prer equisite for success of the BMR. (C) 2000 Elsevier Science Ltd. All rights reserved.