Electrophilic cyclization and concomitant C–Hannulation constitute an expedient cascade strategy for the construction of multicyclic scaffolds with precise substitutional patterns. We report here a novel Pd-catalyzed cyclative annulation of ynone oxime with activated alkynes. The cascade features a dual regioselectivity including site selective C–H activation and chelation-assisted selective insertion
Catalyst Control in Positional-Selective C–H Alkenylation of Isoxazoles and a Ruthenium-Mediated Assembly of Trisubstituted Pyrroles
作者:Pravin Kumar、Manmohan Kapur
DOI:10.1021/acs.orglett.9b00446
日期:2019.4.5
determining the positional selectivity in C–H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C–H alkenylation product via ruthenium and copper co-catalysis