After defining the scope of RAEs, attention then turned to the scope of the aliphatic aldehyde ). Sterically encumbered aldehydes with b-branching, such as isovaleraldehyde (3af) and citronellal (3ag) were competent coupling partners. a-Branched aldehydes (3as-3au) also delivered the desired products without diminished efficiency. Benzyl ethers (3ah), silyl ethers (3ai), acetals (3aj), alkynes (3ak), and phthalimide groups (3ar) were also tolerated. Substrates with functional groups known to engage in transition-metal-catalyzed transformations such as aryl chlorides (3al), aryl bromides (3am) and aryl boronate esters (3an), delivered the desired product smoothly without competing reactivity. Notably, heterocycle substrates, such as indole (3aq), was likewise suitable for this chemistry. The scope and chemoselectivity of this method in activating aldehydes in the presence of a wide array of reactive functional groups including ketones is thus quite broad, addressing an important limitation of classical methods for carbonyl additions. While this method demonstrates considerable scope with carboxylic acid-derived RAEs, we considered that utilizing alkyl precursors derived from simple alcohols and alkenes would further extend the utility and scope of the strategy (Table ). To enable the use of alcohol precursors, we explored the use of alkyl tosylates as the coupling partner. With simple modification of the reaction conditions (see SI), our catalytic system can activate the C-O bond of tosylates, delivering the desired product in good yield (Table ) with attractive functional group compatibility including esters (5b), ethers (5c), and furans (5d).