Palladium-Catalyzed Unactivated C(sp3)–H Bond Activation and Intramolecular Amination of Carboxamides: A New Approach to β-Lactams
摘要:
An efficient method to synthesize the beta-lactams with high regioselectivity via Pd-catalyzed C(sp(3))-H bond activation and intramolecular arnination of simple and readily available aminoquinoline carboxamides was demonstrated. C6F5I plays a significant role in the formation of the C-N bond of the four-membered ring beta-lactams. High yield along with wide substrate scope and functional group tolerance makes this reaction applicable to build natural-product-derived beta-lactams. This method has been applied to the efficient synthesis of the beta-lactamase inhibitor MK-8712.
Stereoselective Synthesis of Diazabicyclic β-Lactams through Intramolecular Amination of Unactivated C(sp<sup>3</sup>)–H Bonds of Carboxamides by Palladium Catalysis
An efficient C(sp3)–H bond activation and intramolecular amination reaction via palladiumcatalysis at the β-position of carboxyamides to make β-lactams was described. The investigation of the substrate scope showed that the current reaction conditions favored activation of the β-methylene group. Short sequences were developed for preparation of various diazabicyclic β-lactam compounds with this method
Direct Arylation of Primary and Secondary sp<sup>3</sup> C–H Bonds with Diarylhyperiodonium Salts via Pd Catalysis
作者:Fei Pan、Peng-Xiang Shen、Li-Sheng Zhang、Xin Wang、Zhang-Jie Shi
DOI:10.1021/ol402116a
日期:2013.9.20
Palladium-catalyzed primary and secondary sp3 C–H bond arylation is reported. The method using diarylhyperiodonium salts as arylation reagents shows good functional group tolerance and proceeds under mild reaction conditions. The KIE experiments show that the C–H bond activation is the rate-determining step.
Transition Metal‐Controlled Direct Regioselective Intermolecular Amidation of C−H Bonds with Azodicarboxylates: Scope, Mechanistic Studies, and Applications
A simple and efficient transition metal‐catalyzed C−Hamidation with azodicarboxylates has been developed. Under silver catalysis, the amide substrates undergo regioselective C−Hamidation at C5‐position of the quinoline. Conversely, with palladium as the catalyst, the reaction gave β‐C(sp3)−H amidation products via the activation of methylene C(sp3)−H bonds. Mechanistic studies suggested that the