Sequential column asymmetric catalysis.

Since the introduction of catalysts and reagents on solid-support, researchers have developed new reaction systems to take advantage of their insoluble nature by designing multistep reaction sequences, high-throughput purification techniques, and combinatorial synthesis methods. The continuous flow system is one of these advancements and represents the foundation of a new technique termed sequential column asymmetric catalysis (CAC). In this strategy, reagents and catalysts are attached to a solid-phase support and loaded onto sequentially-linked columns. The substrates are present in the liquid phase that flows through the column. As a substrate encounters each successive column, it grows in complexity. Consequently, one can imagine a number of flow systems that consist of columns attached in series and/or in parallel that synthesize a fairly complex molecule. Herein, we discuss the development of the sequential CAC technique, beginning with the most relevant antecedents.