Catalytic C-H Arylation of Aliphatic Aldehydes Enabled by a Transient Ligand.

The direct arylation of aliphatic aldehydes has been established via Pd-catalyzed sp3 C-H bond functionalization in the presence of 3-aminopropanoic acids as transient directing groups. The reaction showed excellent functional group compatibility and chemoselectivity in which a predominant preference for functionalizing unactivated β-C-H bonds of methyl groups over others was achieved. In addition, C-H bonds of unactivated secondary sp3 carbons can also be functionalized. The extreme popularity and importance of aliphatic aldehydes would result in broad applications of this novel method in organic chemistry and medicinal sciences.