The presence of a quaternary centre—a carbon with four other carbons bonded to it—in any given molecule can have a substantial chemical and biological impact. In many cases, it is enabling, as in the Thorpe–Ingold effect, which gives rise to large rate enhancements in cyclization reactions, including applications in drug delivery for molecules with modest bioavailability.1 Similarly, the addition of quaternary centres to a drug candidate can enhance both activity and metabolic stability.2 When present in chiral ligands,3 catalysts,4 and auxiliaries,5 quaternary centres can guide reactions to both improved and unique regio-, stereo- and/or enantioselectivity. Yet their formation is often a handicap, because their distinct steric congestion and conformational restriction is reliably handled by only a few chemical transformations.6,7 For particularly challenging cases, as in the vicinal all-carbon,8 oxa-, and aza-quaternary centres9 in molecules such as azadirachtin,10,11 scopadulcic acid A12,13 and acutumine,14 the development of target-specific approaches along with multiple functional-group and redox manipulations is often necessary. Given this apparent dichotomy, other ways for quaternary centres to positively affect and guide synthetic planning should exist. Here we show that if a synthesis is designed such that each quaternary centre is deliberately leveraged to simplify the construction of the next, either through rate acceleration or blocking effects, highly efficient, scalable and modular syntheses can result. This approach is exemplified here using the conidiogenone family of terpenes as a representative case, but this framework provides a distinct planning logic applicable to other targets of similar synthetic complexity that contain multiple quaternary centres.