Is Organic Chemistry Really Growing Exponentially?

Abstract

In terms of molecules and specific reaction examples reported in the literature, organic chemistry features an impressive, exponential growth. However, new reaction classes/types that fuel this growth are being discovered at a much slower and only linear (or even sublinear) rate. In effect, the proportion of newly discovered reaction types to all reactions being performed keeps decreasing, suggesting that synthetic chemistry becomes more reliant on reusing the well-known methods. On the brighter side, the newly discovered chemistries are more complex than decades ago, and allow for the rapid construction of complex scaffolds in fewer numbers of steps. In this paper, we study these and other trends in the function of time, reaction-type “popularity” and complexity based on the algorithm that extracts generalized reaction class templates. These analyses are useful in the context of computer-assisted synthesis, machine learning (to estimate the numbers of models with sufficient reaction statistics), and also for identifying erroneous entries in reaction databases.