Chemical Problems Organic synthesis

One of the cornerstones of combinatorial synthesis has been the development of solid-phase organic synthesis (SPOS) based on the original Merrifield method for peptide preparation [19]. Because transformations on insoluble polymer supports should enable chemical reactions to be driven to completion and enable simple product purification by filtration, combinatorial chemistry has been primarily performed by SPOS [19-23], Nonetheless, solid-phase synthesis has several shortcomings, because of the nature of heterogeneous reaction conditions. Nonlinear kinetic behavior, slow reaction, solvation problems, and degradation of the polymer support, because of the long reactions, are some of the problems typically experienced in SPOS. It is, therefore, not surprising that the first applications of microwave-assisted solid-phase synthesis were reported as early 1992 [24],... 

A major cause of this problem in organic synthesis is the fact that many of the synthetic tools were developed without knowledge of how nature was performing its chemistry. We now have the heritage of many powerful chemical conversion procedures with a great variety in reaction conditions such as temperature, pressure, solvent, air and moisture sensitivity. In other words, procedures that as such are of great value but lack the possibility to be combined in a cascade mode of conversion for the multi-step syntheses frequently required for specialities. 

The fourth section, on organic synthesis, discusses methods to construct complex organic syntheses using simple one-step reactions. Many groups have used the computer to search for synthetic pathways for chemical synthesis in the past. Each approach must deal with the problem of multiple possible pathways for each step in the reaction. The chapters in this section apply AI techniques to select good paths in the synthesis. 

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