Palladium‐Catalyzed PIDA‐Mediated δ‐C(sp(3))−H Acetoxylation of Amino Acid Derivatives: Overriding Competitive Intramolecular Amination

The selective δ‐C(sp(3))−H acetoxylation of N‐(SO(2)Py)‐protected amino acid derivatives has been accomplished by using palladium‐catalysis and PhI(OAc)(2) (PIDA) as both terminal oxidant and acetoxy source. The distinct structural and electronic features of the SO(2)Py compared to more traditional carbonyl‐based directing groups is essential to override the otherwise more favourable competitive intramolecular C−H amination. The δ‐site selectivity predominates over traditionally more favorable 5‐membered cyclopalladation at competitive γ‐CH(2). Experimental and DFT mechanistic studies provide important insights about the mechanism and the underlying factors controlling the chemo‐ and regioselectivity.