Presents an desirable strategy for the synthesis of vicinal diamines and
Presents an attractive technique for the synthesis of vicinal diamines and has received considerable interest especially in current years. Significant progress has2014 American Chemical SocietyAccounts of Chemical ResearchArticleScheme two. Pd(0)-Catalyzed DiH3 Receptor MedChemExpress amination of Olefins UsingFigure 1. Chosen examples of 1,2-diamine-containing biologically active molecules.Scheme 3. Proposed Catalytic Cycle for the Diamination of Olefins withFigure 2. Di-tert-butyldiaziridinone (1) and its related analogues (two and three).butyldiaziridinone (1) and its connected analogues (Figure two) are hugely powerful agents for the diamination of olefins within the presence of Pd(0) or Cu(I) catalyst. This account summarizes our research on this subject.2. Pd(0)-CATALYZED DIAMINATION By way of N-N BOND ACTIVATION Inspired by our research around the epoxidation of olefins by means of threemembered dioxiranes,12 we’ve got explored the possibility toScheme 1. Diamination of Olefins via N-N Bond Activationinstall nitrogen atom(s) onto C-C double bonds with associated three-membered nitrogen analogues. It was envisioned that a metal could oxidatively add to the N-N bond of diaziridine 4 to kind diamido species five, which could react with an olefin to give amination item 7 through migratory insertion to the double bond and subsequent reductive elimination (Scheme 1). Along this line, numerous metal catalysts, three-membered diaziridines, and olefin substrates had been investigated. It was located that various conjugated 1,3-dienes could be regio- and diastereoselectively diaminated in the CYP51 site internal double bond with Pd(0) as catalyst and di-tert-butyldiaziridinone (1) as nitrogen source, giving the corresponding imidazolidinones in higher yields (Scheme 2).13,14 Each electron-rich and electrondeficient conjugated dienes had been identified to be powerful substrates. When a conjugated triene was made use of, the diamination also occurred cleanly in the middle double bond. The amount of Pd(0) catalyst can be decreased from ten to 1-2 mol by slow addition of di-tert-butyldiaziridinone (1) below solvent-free conditions.15,14b However, cis-dienes had been not productive substrates beneath the present reaction conditions. A plausible catalytic pathway for the diamination is outlined in Scheme 3 determined by the NMR and kinetic research.13,15 The Pd(0) initial oxidatively inserts into the N-N bond of di-tertbutyldiaziridinone (1) to kind four-membered Pd(II) species 10, which undergoes a ligand exchange to provide Pd(II) olefin complicated 11. Upon a migratory insertion, complex 11 is converted into -allyl Pd species 12, which undergoes a reductive elimination to kind diamination product 9 and regenerate the Pd(0) catalyst. The symmetric four-membered Pd(II) intermediate (10) can be detected by 1H NMR spectroscopy. It was formed when di-tert-butyldiaziridinone (1) was treated with Pd(PPh3)4 and steadily disappeared upon addition of (E)-1-phenylbutadiene (8a) (Figure three).15 Also, the four-membered Pd(II) species (ten), generated from Pd(OAc)2-PPh3 (1:two) and dilithium salt of di-tertbutylurea (14), also regioselectively diaminated (E)-1,3pentadiene (8b) in the internal double bond to give thedx.doi.org10.1021ar500344t | Acc. Chem. Res. 2014, 47, 3665-Accounts of Chemical ResearchArticleFigure 3. 1H NMR monitoring from the reaction between di-tert-butyldiaziridinone (1) and Pd(PPh3)4, at the same time because the subsequent diamination of (E)-1phenylbutadiene (8a).Scheme 4. Diamination of (E)-1,3-Pentadiene with FourMembered Pd(II) Speciesdiamination solution in 38.