Synthesis of [1,2-a]-fused tricyclic dihydroquinolines by palladium-catalyzed intramolecular C–N cross-coupling of polarized heterocyclic enamines
作者:Břetislav Brož、Zdeňka Růžičková、Petr Šimůnek
DOI:10.3998/ark.5550190.p009.723
日期:——
A simple methodology for [1,2-a]-fusedtricyclicdihydroquinolines is established. The key step of the methodology is an intramolecular Buchwald-Hartwig amination reaction of suitable halogenated (both bromo and chloro) cyclic enaminoketones, enaminoesters and enaminonitriles with various ring size (from fiveto seven-membered). Optimal reaction conditions (palladium source, base, ligand) depend on
Abstract Acetyl-substituted heterocyclic enamines 4 were synthesized from lactim ethers 2 and acetylacetone through condensation and deacetylation reactions, and they, along with the ester-substituted heterocyclic enamines 6, reacted with diethylazodicarboxylate to afford C-adducts 7 and 8 in excellent yields.