Copper-mediated cyclopropanation of 1,3-dialkyl-1,3-dihydroimidazol-2-ones with diazomethane and methyl diazoacetate yields 2,4-diazabicyclo[3.1.0]hexan-3-ones and the first diaza[4.3.1]propellane. The bicyclic system survives elevated temperatures and in strongly basic and acidic solutions, but drastic conditions cleave the (C-1) (C-6) bond affording 1,3-dihydroimidazol-2-ones. Catalytic hydrogenation removes N-benzyl groups and opens the (C-1) (C-6) bond. Lithium aluminium hydride reduces 2,4-dibenzyl-2,4-diazabicyclo[3.1.0]hexan-3-one to a bicyclic aminal. Acid-induced cleavage of its imidazolidine ring is followed by unexpected transformations that probably procede via an acyclic intermediate, which comprises an azomethine ylide and an iminium moiety. 1,3-Cyclization involving both functional groups leads to N,N'-dibenzyl-trans-1,2-cyclopropanediamine, while 1,5-cyclization gives rise to the formation of N-benzylpyrrole along with N-benzylamine.
Synthesis of Imidazolidinone, Imidazolone, and Benzimidazolone Derivatives through Oxidation Using Copper and Air
作者:Dazhi Li、Thierry Ollevier
DOI:10.1021/acs.orglett.9b00973
日期:2019.5.17
synthetic method of urea derivativesusing copper and air was developed. These mild conditions provided moderate to very good yields for 15 examples (53–93%), while low yields were obtained with sterically hindered substrates (3 examples). The reaction was found to go through an in situ generated copper–N-heterocyclic carbene, which was then oxidized into cyclic urea derivatives possessing alkyl, benzyl
Mechanism studies of oxidation and hydrolysis of Cu(I)–NHC and Ag–NHC in solution under air
作者:Dazhi Li、Thierry Ollevier
DOI:10.1016/j.jorganchem.2019.121025
日期:2020.1
The decomposition of copper(I)–NHC and silver-NHC complexes in solution under air was studied. The Cu(I)–NHCs were oxidized into urea derivatives and hydrolysed into imidazoliums or benzimidazoliums. The decomposition of Ag–NHC with a saturated backbone led to ring-opening product, while the Ag–NHC with an unsaturated backbone led to imidazolium and Ag-bisNHC complex. The effects of steric property
Chemoselective Electrosynthesis Using Rapid Alternating Polarity
作者:Yu Kawamata、Kyohei Hayashi、Ethan Carlson、Shobin Shaji、Dirk Waldmann、Bryan J. Simmons、Jacob T. Edwards、Christoph W. Zapf、Masato Saito、Phil S. Baran
DOI:10.1021/jacs.1c06572
日期:2021.10.13
in the selective manipulation of functional groups (chemoselectivity) in organic synthesis have historically been overcome either by using reagents/catalysts that tunably interact with a substrate or through modification to shield undesired sites of reactivity (protecting groups). Although electrochemistry offers precise redox control to achieve unique chemoselectivity, this approach often becomes challenging
Selective Catalytic Monoreduction of Phthalimides and Imidazolidine-2,4-diones
作者:Shoubhik Das、Daniele Addis、Leif R. Knöpke、Ursula Bentrup、Kathrin Junge、Angelika Brückner、Matthias Beller
DOI:10.1002/anie.201104226
日期:2011.9.19
Fluoride's new role: Selective and efficient monoreductions of imides can be achieved with polymethylhydrosiloxane (PMHS) and tetra‐n‐butylammonium fluoride (TBAF) as catalyst (see scheme). The system is characterized by good chemoselectivity, operational simplicity, and functional‐group tolerance; a concise mechanistic proposal was possible from in situ spectroscopic investigations.
Efficient Solid-Phase Synthesis of Disubstituted 1,3-Dihydro-imidazol-2-ones
作者:Gérard Rossé、Julie Strickler、Marcel Patek
DOI:10.1055/s-2004-831316
日期:——
A bromoacetal linker was used to achieve the synthesis of ureas on a solid support. The resulting ureido acetals were treated with TFA and were converted in an intramolecular cyclization via N-acyliminium ion to disubstituted 1,3-dihydro-imidazol-2-ones.