Dual C(sp)-H and C(sp)-H Activation of 8-Methylquinoline -Oxides: A Route to Access C7-H Bond.

A Pd(II)-catalyzed regioselective dual C(sp)-H/C7(sp)-H activation and annulation of 8-methylquinoline -oxides with maleimide has been accomplished. The use of -oxide as a weak directing group under Pd(II)-complex catalysis activates the initial C(sp)-H and triggers a relayed, second C7(sp)-H activation. The dual C-H bond activation, [3 + 2]-annulation, facile introduction and removal of the directing group, substrate scope, and functional group diversity are the important practical features.

Palladium Catalysis Enabled Sequential C(sp)-H/C-C Activation: Access to Vinyl γ-Lactams.

A Pd(II)-catalyzed tandem reaction of aliphatic amides with vinylcyclopropanes (VCPs) was accomplished by merging C(sp)-H and C-C activation. The reaction of VCP revealed alkenylation/cyclization, followed by ring opening via C-C cleavage, delivering vinyl γ-lactams with ()-selectivity. The role of ligands, site-selectivity, functional group diversity, mechanistic insight, and synthetic utilities are important practical features.

Site-Selective C8-Alkylation of Quinolines with Cyclopropanols: Merging C-H/C-C Bond Activation.

The site-selective C8-alkylation of quinolines has been accomplished using cyclopropyl alcohols as the alkylating agents and -oxide as a weak chelating group in the presence of Co(III) catalysis via merging C-H/C-C bond activation. The use of cyclopropanol as the alkyl source, Co catalysis, substrate scope, HRMS analysis of the reaction intermediate, and late-stage mutation of drug molecules/natural products are the important practical features.