Sulfonamide‐Promoted Palladium(II)‐Catalyzed Alkylation of Unactivated Methylene C(sp 3 )H Bonds with Alkyl Iodides

The alkylation of unactivated β‐methylene C(sp 3 )H bonds of α‐amino acid substrates with a broad range of alkyl iodides using Pd(OAc) 2 as the catalyst is described. The addition of NaOCN and 4‐Cl‐C 6 H 4 SO 2 NH 2 was found to be crucial for the success of this transformation. The reaction is compatible with a diverse array of functional groups and proceeds with high diastereoselectivity. Furthermore, various β,β‐hetero‐dialkyl‐ and β‐alkyl‐β‐aryl‐α‐amino acids were prepared by sequential C(sp 3 )H functionalization of an alanine‐derived substrate, thus providing a versatile strategy for the stereoselective synthesis of unnatural β‐disubstituted α‐amino acids.