This reactivity order set chemistry information potentially permits streamlining the deductive synthetic strategy is of vital importance. Set chemistry takes chemistry set, a collection of transformations with defined (especially quantitative) reactivity relations, rather than individual transformation, as the fundamental unit for synthetic planning. A chemistry set can bundle together transformations with both similar and dissimilar reactivity patterns. The identification of reactivity patterns can itself be a reactivity development tool that leads to the expansion of a chemistry set. Set chemistry can expectedly rewrite synthetic rules governing many of the organic transformations, thus contributing to both retrosynthetic planning and forward reactivity analysis.