Although such a motif is a prime target for Diels-Alder approaches, accessibility and stability of the reactants, as well as polarity matching, is not always trivial. For example, access to olefinic sulfone 5 can be laborious (previously reported in 7 steps), whereas electrochemical decarboxylation allows its preparation in a single step from the commercially available acid ($5.4/g). Similarly, the synthesis of 4-aminocyclohexene derivatives 6 and 7 from a readily available carboxylic acid ($4.8/g, free amine) also exemplifies the potential of this protocol to circumvent a cumbersome Diels-Alder/Curtius rearrangement sequence. Medicinally relevant gemfibrozil, used as a lipid regulator to treat high cholesterol, offers an intriguing case study on chemoselectivity. The electron-rich alkyl aryl ether prone to electrochemical oxidation was tolerated in the decarboxylative olefination, highlighting the chemoselective nature of the oxidation process. The method also allows facile derivatization of naturally occurring carboxylic acids such as ursolic acid, isosteviol, and dehydroabietic acid to deliver unique olefins with complex polycyclic scaffolds (14-16). Interestingly, in the case of camphoric acid, the tertiary acid was selectively decarboxylated to afford g,d-unsaturated acid 13. Simple primary carboxylic acids-the most abundant yet least prone to undergo Hofer-Moest-are efficiently decarboxylated under this protocol. Oleic acid, a common component of plant oil, can be turned into an exotic diene 19, while suberic acid monomethyl ester can be converted into a valuable unsaturated ester 20 ($160/g). In addition to olefin product formation, this protocol demonstrates different reaction outcomes based on the nature of the carbocation intermediate. b-Hydroxy acid 8 can readily undergo decarboxylation followed by pinacol-type rearrangement to form cyclic ketone 9, while adamantanol derivative 17 efficiently leads to Grob fragmentation product 18. Another unique evidence of carbocation intermediacy was obtained in the decarboxylation of a primary acid, where the formation of alkene 22 was accompanied by cyclopropane 21. This byproduct formation invokes a non-classical carbocation stabilization followed by a new C-C s-bond formation via gdeprotonation. Since oxidative decarboxylation is balanced by reduction of acetone used as solvent, confirmed by the detection of ~1.0 equiv. of isopropanol in crude H NMR (see SI), functional groups susceptible to electron-transfer within the redox window of carboxylate and acetone might not be tolerated (Table , bottom left). Therefore, reductively labile functionalities such as alkyl halides (23), aryl sulfonamides (24), electron-poor heterocycles (25), or enones (26) were not amenable to the current reaction conditions. Similarly, tertiary alkyl amines (27) or electron-rich heterocycles (28) interfered with oxidative decarboxylation. In certain cases, olefin formation provided an inseparable mixture of isomers. In this scenario, the mixture could be converted into a single product by enlisting alkene isomerization conditions (Table , bottom right), using the recently reported electrocatalytic generation of Co-H to access the internal isomer 12b. The ultimate proving ground for this simple, metal-free protocol is in its applicability to be conducted on a large scale. Thus, we partnered with AbbVie process chemists to scale the electrochemical decarboxylative olefination of carboxylic acid 2 (Figure ). Translation of the method to the continuous stirred-tank reactor (CSTR), employing a cylindrical electrode array (Figure , top right), was straightforward. Equivalents of base and sacrificial additive were modified, and the electrolysis mode was switched from constant current to constant potential, to improve the current flow and minimize reaction time. Since the AbbVie reactor (see SI) allows facile optimization of reaction temperature, it was fine-tuned to 35 ºC. Overall, in less than 10 lab experiments on 7 g scale, suitable conditions were identified for scale-up. Notably, the reaction stalled when DC electrolysis was employed (Figure , top left), confirming that the importance of alternating polarity is universal across various reactions scales. Increasing the scale of the reaction from 7 to 28 g in a larger reactor led to nearly identical reaction performance (Figure , bottom left). This preliminary scale-up effort successfully demonstrated that scaling the reaction based on electrode surface area would lead to predictable results. Thus, further scale-up to 1 kg was undertaken by simply using a larger electrode array (Figure , top right). The surface area of this electrode supposes a ten-fold increase relative to the array used for the 28 g reaction and fits into an 8 L reactor body. To achieve a batch reaction size of 1 kg in this reactor, the reaction was further concentrated from ~0.25 M under the nominal conditions to 0.8 M without consequence.