Split-mix technique

What is clear is that all of these early combinatorial experiments had their basis in the solid-phase peptide synthesis developed in 1964 by Bruce Merrifield (see chapter 7). The Furka split-mix technique is outlined in the figure on page 337. For the sake of brevity, only 3 different components (X, Y, and Z) are depicted and only trimers (3 steps) are depicted so that the library has 3 entries (combinations). In practice, Furka was initially interested in peptide synthesis. If all 20 common amino acids are employed to make a library of pentapeptides, then the number of entries is 20 or 3.2 million. For a decapeptide, the library would have 1.02 x 10 entries. The use of solid-phase beads serves two purposes ... 

FMS is an elegant application of fluorous chemistry. Its solution-phase reaction kinetics, the split-mix technique, and separative fluorous tags expedite synthesis by increasing the speed, efficacy, and purity (Scheme 7.3). It is especially suitable for the combinatorial synthesis of a large number of compounds in larger quantities than existing mixture synthesis techniques. The synthesis usually begins with... 

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