Highly Efficient Syntheses of Azetidines, Pyrrolidines, and Indolines via Palladium Catalyzed Intramolecular Amination of C(sp<sup>3</sup>)–H and C(sp<sup>2</sup>)–H Bonds at γ and δ Positions
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
The Iodine-mediated oxidative intramolecular amination of anilines via cleavage of unactivated (sp3)C–H and N–H bonds for the production of indolines is described. This transition-metal-freeapproach provides a straightforward strategy for producing (sp3)C–N bonds for use in the preferential functionalization of unactivated (sp3)C–H bonds over (sp2)C–H bonds. The reaction could be performed on a gram
develop a new “cobalt(II)/organic oxidant” catalytic system for the selective activation of 1°, 2°, and 3° C(sp3)–H bonds to construct C–N and C–O bonds, respectively. The method highlights the use of an organic compound (TsNHOPiv or its analogues) as an emerging oxidant and thus provides a flexible strategy for the preparation of indoline and benzoxazine derivatives. Attractive advantages of this cobalt
A general palladium catalyzed acetoxylation of benzylicC–H bonds has been developed. Picolinamides serve as an excellent directinggroup for the C–H activation of benzylic methyls. A wide range of 2-amino benzyl alcohol analogues were synthesized in good yields. The products demonstrated broad synthetic utilities toward various benzo-fused heterocycles. Mechanistic studies revealed the key rate-limiting
A method for five- and six-membered heterocycle formation by palladium-catalyzed C-H/N-H coupling is presented. The method employs a picolinamide directing group, PhI(OAc)(2) oxidant, and toluene solvent at 80-120 degrees C. Cyclization is effective for sp(2) as well as aliphatic and benzylic sp(3) C-H bonds.