5041-27-0Relevant academic research and scientific papers
Palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate: A practical synthesis of unsymmetrical ureas
Vinogradova, Ekaterina V.,Fors, Brett P.,Buchwald, Stephen L.
supporting information; experimental part, p. 11132 - 11135 (2012/08/28)
An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and N,N,N'-trisubstituted ureas in one pot and is tolerant of a wide range of functional groups. Insight into the mechanism of aryl isocyanate formation was gleaned through studies of the transmetalation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate.
Highly diastereo- and enantioselective reactions of enecarbamates with ethyl glyoxylate to give optically active syn and anti α-alkyl-β- hydroxy imines and ketones
Matsubara, Ryosuke,Nakamura, Yoshitaka,Kobayashi, Shu
, p. 3258 - 3260 (2007/10/03)
The remarkably selective addition of enecarbamates 2 to ethyl glyoxylate (1) in the presence of a copper-dilmine catalyst (0.1 mol%) gives the corresponding imines 3 in high yields with excellent enantioselectivities. A concerted aza-enetype reaction mech
Highly diastereo- and enantioselective reactions of enecarbamates with an aldehyde
Matsubara, Ryosuke,Vital, Paulo,Nakamura, Yoshitaka,Kiyohara, Hiroshi,Kobayashi, Shu
, p. 9769 - 9784 (2007/10/03)
Catalytic asymmetric addition reactions of enecarbamates with ethyl glyoxylate have been developed using CuClO4·4CH3CN and a diimine ligand as the catalyst. Highly diastereo- and enantioselective addition reactions of α-mono-substitu
Preparation of highly substituted 4-aminopyridones via the reaction of 2-methylene dihydrobenzimidazole with vinyl isocyanates
Rigby, James H.,Lee, Chee-Seng
, p. 1151 - 1153 (2007/10/03)
(Matrix presented) The rapid construction of highly substituted 4-aminopyridones was achieved employing an efficient cyclization between various vinyl isocyanates and 2-methylene dihydrobenzimidazole.
Bis(alkylthio)carbenes as novel reagents for organic synthesis
Rigby, James H.,Laurent, Stephane,Dong, Weitong,Danca
, p. 10101 - 10111 (2007/10/03)
Bis(alkylthio)carbenes have been shown to be a useful class of reactive intermediates for applications to organic synthesis. Substituted hydroindolones, isatins and hydroquinolones can be prepared by the addition of these carbenes to vinyl isocyanates. (C) 2000 Elsevier Science Ltd.
Construction of the azepinoindole core tricycle of the Stemona alkaloids
Rigby, James H.,Laurent, Stephane,Cavezza, Alexandre,Heeg, Mary Jane
, p. 5587 - 5591 (2007/10/03)
The azepinoindole substructure common to a number of Stemona alkaloids is constructed by employing a 7-endo radical cyclization of a readily available N-alkylated hydroindolone substrate. The indolone precursors are prepared via [1 + 4] cycloaddition between a vinyl isocyanate and either dimethoxycarbene or cyclohexylisocyanide.
Total synthesis of (±)-α-lycorane and 4,5-dehydroanhydrolycorine
Rigby, James H.,Mateo, Mary E.
, p. 10569 - 10582 (2007/10/03)
The total syntheses of (±)-α-lycorane and dehydroanhydrolycorine are described. The key intermediate in both approaches is the hydroindolone 5, prepared from the [1 + 4] cycloaddition reaction of 1-isocyanatocyclohexene and cyclohexyl isocyanide. Alkylation of 5 with arylbromide 6 afforded 7. Hydrolysis of enamide 7 followed by reduction of the resultant enol yielded 10 as a single diastereomer. Radical-based cyclization of this intermediate gave 11 possessing the requisite trans-fusion between rings B and C in good yield. Radical deoxygenation followed by reduction of the amide carbonyl function afforded (±)-α-lycorane. Similarly, alkylation of 5 with 6-(chloromethyl)-5-iodo-1,3-benzodioxole gave 14. Treatment of 14 with Pd(OAc)2 employing the Jeffery modification of the Heck reaction gave tetracycle 9. Hydrolysis of 9 followed by oxidation with DDQ afforded 15. Reduction of the two carbonyl functions in this material using lithium aluminum hydride afforded 4-hydroxyanhydrolycorine (16). Mesylation of the hydroxyl group led to rapid, spontaneous elimination producing anhydrodehydrolycorine.
(1+4) Cycloaddition of Vinyl Isocyanates with Isocyanides. Construction of Functionally Elaborate Pyrrolinone Derivatives
Rigby, James H.,Qabar, Maher,Ahmed, Gulzar,Hughes, Robert C.
, p. 10219 - 10228 (2007/10/02)
Reaction of alkyl isocyanides with vinyl isocyanates affords highly functionalized pyrrolinone and hydroindolone products via a novel (1+4) cyclization process.
An Experimentally Convenient Preparation of Highly Substituted Pyridines
Rigby, James H.,Qabar, Maher
, p. 2699 - 2709 (2007/10/02)
A four step sequence is described for the conversion of α,β-unsaturated carboxylic acids into highly substituted pyridines.
