Computer-aided synthesis design: 40 years on

The discipline of retrosynthetic analysis is now just over 40 years old. From the earliest day, attempts were made to incorporate this approach into computer programs to test the extent in which chemical perception and synthetic thinking could be formalized. Despite pioneering research efforts, computer-aided synthetic analysis failed to achieve widespread routine use by chemists, which can be attributed in part to the difficulty of building the required high-quality retrosynthetic transform databases required for credible analyses. However, with the advent over the past 25 years of large comprehensive reaction databases, work on successfully automating the construction of reliable and comprehensive reaction rule databases is promising to revitalize research in this field. This review compares and contrasts the diverse approaches taken by selected programs in both the design and implementation of molecule feature perception and reaction rule representation, and we review the concepts of synthetic strategy selection, representation, and execution. In particular, we discuss the current work on automating the construction of reliable and comprehensive synthetic rule sets from available reaction databases in newer programs such as ARChem. We argue that the progress achieved in this aspect paves the way to a deeper exploration of computer approaches to applying strategy and control in the synthesis problem. (c) 2011 John Wiley & Sons, Ltd.