- Radical [1,3] Rearrangements of Breslow Intermediates
-
Breslow intermediates that bear radical-stabilizing N substituents, such as benzyl, cinnamyl, and diarylmethyl, undergo facile homolytic C-N bond scission under mild conditions to give products of formal [1,3] rearrangement rather than benzoin condensatio
- Alwarsh, Sefat,Xu, Yi,Qian, Steven Y.,McIntosh, Matthias C.
-
-
Read Online
- Piano-stool benzothiazol-2-ylidene Ru(II) complexes for effective transfer hydrogenation of carbonyls
-
Benzothiazolium bromides (NSHC.HBr) (1a-j) with a variety of alkyl chain or benzyl substituents on N atom were prepared. The synthesis of ruthenium(II) (NSHC) complexes, (2a–j) could be achieved by in situ deprotonation of benzothiazolium salts with Ag2O and [RuCl2(p-cymene)]2. They were characterized by 1H, 13C, 19F NMR, IR spectroscopy and elemental analysis. The molecular structures of 2d, 2e and 2g were ascertained by single-crystal X-ray diffraction studies. The catalytic properties of complexes, (2a–j), with electron-donating or -withdrawing groups were investigated in transfer hydrogenation (TH) of ketones, and aldehydes with good to excellent yields. The presence of the CH2(CH2)16CH3 or CH2C6F5 on the N atom of the benzothiazol-2-ylidene complexes (2g, 2j) showed the highest activity for TH reaction. The catalytic properties of the N-alkyl substituted ruthenium(II) (NSHC) complexes(2h–j) may be interpreted by micelle effects.
- Oru?, Zeynep ?pek,G?k, Lütfiye,Türkmen, Hayati,?ahin, Onur,Büyükgüng?r, Orhan,?etinkaya, Bekir
-
-
- An efficient procedure for the synthesis of phenacyl and benzyl azolium salts using fluorous alcohols
-
An efficient procedure for the synthesis of phenacyl and benzyl azolium salts in 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoroisopropanol as fluorous alcohols have been developed. This synthetic methodology has some advantages with the respect to yield, atom efficiency, solvent and reagents used and wastes generated when compared to the currently in use methods. Using this procedure, a range of phenacyl and benzyl azolium salts can be synthesized with good to excellent yields. The pure salts are separated from the reaction mixture by simple filtration and washing with dry ether.
- Khalafi-Nezhad, Ali,Panahi, Farhad,Yousefi, Reza,Gholamalipour, Yasaman,Sarrafi, Sina
-
p. 1189 - 1196
(2014/08/05)
-
- Unexpected reactivity of diaryl α-diketones with thiazolium carbenes: Discovery of a novel multicomponent reaction for the facile synthesis of 1,4-thiazin-3-ones
-
Diaryl α-diketones do not undergo polarity reversal in the presence of (benzo)thiazolium carbenes but are engaged in a novel multicomponent reaction with water to efficiently give medicinally relevant 1,4-thiazin-3-one heterocycles. Three different sets of conditions have been optimized to furnish the title compounds in fair to excellent yields depending on the electronic properties of α-diketone aromatic substituents and thiazolium or benzothiazolium substrate. A plausible reaction mechanism is also proposed based on the isolation and characterization of the postulated key intermediate and isotopic labeling experiments.
- Bertolasi, Valerio,Bortolini, Olga,Donvito, Adelaide,Fantin, Giancarlo,Fogagnolo, Marco,Giovannini, Pier Paolo,Massi, Alessandro,Pacifico, Salvatore
-
experimental part
p. 6579 - 6586
(2012/09/08)
-
- Ruthenium(II) N,S-heterocyclic carbene complexes and transfer hydrogenation of ketones
-
A series of ruthenium(II) N,S-heterocyclic carbene (NSHC) complexes Ru IIX(RCOO)(PPh3)2(3-R′BzTh) (BzTh = benzothiazol-2-ylidene; R = Me, R′/X = Bz/Br (4), Pri/I (6), Bui/I (8); R = Et, R′/X = Bz/Br (
- Ding, Nini,Hor, T. S. Andy
-
experimental part
p. 10179 - 10185
(2011/01/06)
-
- Formation and crystallographic elucidation of stable [4 + 2]-coordinate nickel(ii) N,S-heterocyclic carbene (NSHC) complexes
-
A series of square-planar N,S-heterocyclic carbene (NSHC) complexes trans-[NiX2(N-RBzTh)2] (BzTh = benzothiazolin-2-ylidene) (R/X = Bz/Br; Me/I; Et/I; Pri/I; Bui/I) have been synthesized and characterized by X-ray single-crystal diffraction analysis. These are the first crystallographically established NSHC complexes of nickel in the literature. The N,S-heterocyclic carbene (NSHC) rings invariably twist away from co-planarity with the metal coordination plane such that the N-substituent moves on top and below the metal to facilitate electrostatic γ-hydride interaction, thus giving an essentially [4 + 2] coordination at the Ni(ii) center. These compounds are active toward reductive Ullmann-type coupling reactions in Bu4NBr showing higher activities towards bromoanisole or bromotoluene than bromobenzene. The complex trans-[NiI2(N-Pr iBzTh)2] with the shortest Ni...H anagostic separation and a near-ideal orthogonal orientation between the carbene and metal planes gives the highest yields.
- Ding, Nini,Zhang, Jun,Hor, T. S. Andy
-
scheme or table
p. 1853 - 1858
(2009/08/08)
-
- THE CRYSTAL AND ELECTRON STRUCTURE OF 3-BENZYLBENZOTHIAZOLIUM BROMIDE
-
3-benzylbenzothiazolium bromide forms colourless needle-like crystals of monoclinic system, space group P21/c, with cell parameters a = 8.315(6), b = 12.323(9), c = 13.140(11)*10-10 m, β = 103.79(6) deg, and Z = 4.The phase problem w
- Kelloe, Eleonora,Kettman, Viktor,Miertus, Stanislav,Vrabel, Viktor,Konecny, Vaclav
-
p. 1864 - 1873
(2007/10/02)
-