C. This work -Unactivated sp 3 -sp 3 cross couplings with aliphatic aldehydes played a crucial role in successful transformation (entries 3-6). A ligand screen revealed that BiOx is uniquely effective when compared with other common ligands (entries 13-15). Of note, olefin additives can dramatically improve the efficiency, with 1,5-hexadiene proving the most effective (entries 5, 8-10). Furthermore, the particle size of Zn is critical, with the use of nanopowder Zn (40-60 nm) enhancing the yield (entry 7). With optimal conditions in hand, we sought to define the reaction scope (Table ). Various 1º and 2º carboxylic acids were converted to the corresponding NHPI-esters and coupled efficiently with aldehyde 1a. A range of functional groups were well tolerated including ketones (3h, 3i, 3ab), esters (3j, 3x), N-Boc (3y), N-tosyl (3z), and alkenes (3g, 3v, 3ac, 3ad). A simple methyl group can also be added effectively using the RAE 3c derived from acetic acid. Notably, some potentially reactive functional groups, including alkyl chloride 3k and aryl bromide 3l were left intact under current conditions, offering opportunities for subsequent cross-coupling. Protected alcohols (3f, 3ac) and ethers (3m, 3t, 3u) were also competent coupling partners, allowing for the construction of polyol motifs. Moreover, heterocycles including pyridine (3o), and indole (3p) were also readily accommodated as were a series of secondary redox-active esters (3q-3z). The protocol was scalable to 5 mmol, obtaining the desired product 3a in 81% isolated yield.