Palladium-Catalyzed PIDA-Mediated δ-C(sp3 )-H Acetoxylation of Amino Acid Derivatives: Overriding Competitive Intramolecular Amination.

The selective δ-C(sp3 )-H acetoxylation of N-(SO2 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 SO2 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-CH2 . Experimental and DFT mechanistic studies provide important insights about the mechanism and the underlying factors controlling the chemo- and regioselectivity.

Access to Benzazepinones by Pd-Catalyzed Remote C-H Carbonylation of γ-Arylpropylamine Derivatives.

A general method for the construction of seven-membered rings through Pd-catalyzed C(sp2)-H carbonylation at the remote ε-position of γ-arylpropylamine derivatives, including chiral α-amino acids, has been developed using Mo(CO)6 as the CO source, furnishing richly functionalized benzo[ c]azepin-1-one derivatives. The readily removable N-SO2Py protecting/directing group provides high levels of chemo-, regio- and diastereoselectivity. Furthermore, this method is amenable to the postsynthetic modification of complex molecules such as small peptides.