A three step, convergent synthesis of 4-aryl-3-pyrrolin-2-ones from a tetramic acid has been developed. The key transformation utilized a Suzuki-Miyaura cross-coupling reaction between a 4-tosyloxy-3-pyrrolin-2-one and an arylboronic acid. This work also provides access to 4-arylpyrrolidin-2-ones, cyclic analogs of gamma-aminobutyric acid (GABA). Hydrogenation of 4-(4'-chloro-phenyl)-3-pyrrolin-2-one proceeded smoothly to give baclofen lactam. (c) 2006 Elsevier Ltd. All rights reserved.
a (ZhaoPhos) catalytic system has been identified for the straightforward asymmetric synthesis of chiral γ-lactams. A variety of NH free α,β-unsaturated lactams bearing a β-aryl or β-alkyl substituent were smoothly hydrogenated to provide the desired γ-lactams in up to 99% yield and 99% enantiomeric excess (ee). This methodology provides a highly practical pathway to synthesize chiral γ-lactams or
Au-allenylidene promoted decarboxylative annulation to access unsaturated γ-lactams/lactones
作者:Xuelun Duan、Haotian Shi、Yangyang Yue、Wangze Song
DOI:10.1039/d4cc00200h
日期:——
A novel Au-allenylidene promoted decarboxylative annulation by intramolecular α-nucleophilic addition has been disclosed. The unsaturated cyclic ethynylethylene carbamates/carbonates can be converted to unique nucleophiles attached with alkylidene ketenes by sequential decarboxylation and oxidation processes. Such alkylidene ketenes can be rapidly trapped by intramolecular α-attacking annulation to
Rh–IndOlefOx catalyzed conjugate addition/Heck-type coupling of organoboronics to a lactam or a lactone
作者:Noora Kuuloja、Matti Vaismaa、Robert Franzén
DOI:10.1016/j.tet.2012.01.040
日期:2012.3
Four indole-olefin-oxazoline (IndOlefOx) ligands were synthesized and evaluated in Rh-catalyzed reactions between organoboronics and a lactam or a lactone. In addition to the expected conjugate addition products, the formation of significant amounts of Heck-type products was observed. The scope and limitations of these reactions were investigated. (C) 2012 Elsevier Ltd. All rights reserved.