Tetraarylphosphonium Salts as Soluble Supports for the Synthesis of Small Molecules

Support groups: Phosphonium salts can be used as solubility-control groups (SCGs) in small-molecule and peptide synthesis (see scheme). The concept, which is a hybrid approach between solution- and solid-phase syntheses, is illustrated by the preparation of 2-substituted piperidine derivatives and a variety of small peptides with high yields and purities. In some cases, recycling of the support is possible.