Efficient methods have been developed to synthesize azetidine, pyrrolidine, and indoline compounds via palladium-catalyzed intramolecular amination of C-H bonds at the γ and δ positions of picolinamide (PA) protected amine substrates. These methods feature relatively a low catalyst loading, use of inexpensive reagents, and convenient operating conditions. Their selectivities are predictable. These methods highlight the use of unactivated C-H bond, especially the C(sp(3))-H bond of methyl groups, as functional groups in organic synthesis.

We report an efficient method for the alkylation of γ-C(sp(3))-H bonds of picolinamide-protected aliphatic amine substrates with primary alkyl iodides via palladium catalysis. Ag(2)CO(3) and dibenzyl phosphate, (BnO)(2)PO(2)H, are critical promoters of this reaction. These reactions provide a convenient and straightforward method for the preparation of high-value N-containing products from readily available amine and alkyl iodide precursors.

We report the efficient synthesis of alkyl ethers by the functionalization of unactivated sp(3)- and sp(2)-hybridized C-H bonds. In the Pd(OAc)(2)-catalyzed, PhI(OAc)(2)-mediated reaction system, picolinamide-protected amine substrates undergo facile alkoxylation at the γ or δ positions with a range of alcohols, including t-BuOH, to give alkoxylated products. This method features a relatively broad substrate scope for amines and alcohols, inexpensive reagents, and convenient operating conditions. This method highlights the emerging value of unactivated C-H bonds, particularly the C(sp(3))-H bond of methyl groups, as functional groups in organic synthesis.

An easily synthesized and accessible N,O-bidentate auxiliary has been developed for selective C-H activation under palladium catalysis. The novel auxiliary showed its first powerful application in C-H functionalization of remote positions. Both C(sp(2))-H and C(sp(3))-H bonds at δ- and ε-positions were effectively activated, thus giving tetrahydroquinolines, benzomorpholines, pyrrolidines, and indolines in moderate to excellent yields by palladium-catalyzed intramolecular C-H amination.

An efficient method has been developed for the synthesis of indoline compounds from picolinamide (PA)-protected β-arylethylamine substrates via palladium-catalyzed intramolecular amination of ortho-C(sp(2))-H bonds. These reactions feature high efficiency, low catalyst loadings, mild operating conditions, and the use of inexpensive reagents.