64841-68-5Relevant academic research and scientific papers
Palladium-Catalyzed Reactions of Allylic Boronic Esters with Nucleophiles: Novel Umpolung Reactivity
Unsworth, Phillip J.,L?ffler, Lorenz E.,Noble, Adam,Aggarwal, Varinder K.
supporting information, p. 1567 - 1572 (2015/06/30)
Oxidative palladium-catalyzed reaction conditions have been developed to allow for regioselective and stereoselective coupling of allylic boronic esters with a range of carbon-, oxygen-, and nitrogen-based nucleophiles. Studies into the mechanism of the r
New homochiral phosphine ligands having a hexahydro-1H-pyrrolo[1,2-c]imidazolone backbone: Preparation and use for palladium-catalyzed asymmetric alkylation of cycloalkenyl carbonates
Shibatomi, Kazutaka,Uozumi, Yasuhiro
, p. 1769 - 1772 (2007/10/03)
New chiral ligands having a pyrrolo[1,2-c]imidazolone backbone were prepared by condensation of anilides of homochiral cyclic amino acids with 2-(diphenylphosphino)benzaldehyde. Of these ligands, (3R,9aS)-(3-(2-diphenylphosphino)phenyl-2-phenyl)tetrahydro-1H-imidazo [1,5-a]indole-1-one was found to be effective for palladium-catalyzed asymmetric allylic alkylation of cycloalkenyl carbonates with dimethyl malonate to give the corresponding dimethyl cycloalkenylmalonates with e.e. of up to 89%.
Nickel catalysed coupling of allylamines and boronic acid
Trost, Barry M.,Spagnol, Michel D.
, p. 2083 - 2096 (2007/10/02)
Allylamines function as substrates for cross-coupling with boronic acids in the presence of nickel(0) catalysts rather than palladium(0) catalysts.Aryl-, vinyl- and methyl-boronic acids function well.With vinyl derivatives, E-isomers couple more efficiently than Z-isomer and both fully retain the geometrical integrity.Methylations preferably employ the boronic esters like 2-methyl-1,3,2-benzodioxaborole or 2-methyl-1,3,2-dioxaborolane rather than methylboronic acid.The stereochemistry of the reaction involves a net inversion with respect to the allylamine.The regioselectivity is a function of ligand.Generally, sterically bulky donor phosphines promote new C-C bond formation at the less substituted position.Bidentate ligands, notably 1,1'-binaphthyl-2,2'-ylbis(diphenylphosphinite) (BINAPO), promote new C-C bond formation at the more substituted allyl terminus.The amines appear to be the preferred partner compared to allyl alcohols and esters with the boronic acids and give higher stereospecificity.
Isomerization of (πr-allyl)palladium complexes via nucleophilic displacement by palladium(0). A common mechanism in palladium(0)-catalyzed allylic substitution
Granberg, Kenneth L.,B?ckvall, Jan-E.
, p. 6858 - 6863 (2007/10/02)
Treatment of (π-allyl)palladium complexes such as 6 and 9 with Pd(PPh3)4 leads to rapid isomerization at -15 °C in tetrahydrofuran and other solvents. At 0°C and in the presence of more than 2 equiv of triphenylphosphine per palladium, the phosphine attacks the T-allyl group to give allylic phosphonium salts 7 with concomitant formation of a palladium(0)-phosphine complex, and isomerization of 6 is observed. Attack by PPh3 on 6 was shown to be stereospecific and to proceed with inversion. Studies of the Pd(0)-catalyzed substitution of le (X = OAc) with several different nucleophiles support the hypothesis that Pd(0) acts as a nucleophile on (π-allyl)palladium complexes, in a reaction that leads to loss of stereospecificity in these systems.
Asymmetric Allylic Alkylation Catalyzed by Palladium-Sparteine Complexes
Togni, Antonio
, p. 683 - 690 (2007/10/02)
The cationic complex 3-C3H5)(sparteine)>PF6 (6) was found to be a suitable catalyst precursor for the asymmetric alkylation of allylic acetates with Na as the nucleophile.This constitutes one of the first and still rare examples of a phosphine-free system for this type of Pd-catalyzed reaction.Using 5 mol percent of 6, alkylation products were obtained in up to 90 percent isolated yield and 85 percent enantiomeric excess.The alkylation reaction was shown to occur with overall retention of configuration, indicating an analogous mechanism to the one previouslyproposed for phosphine-containing catalysts.The reactivity of allylic acetates is strongly dependent upon the nature of the substituents, open-chain aliphatic substrates being unreactive.
Ligand dependence of molybdenum-catalyzed alkylations. Molybdenum-isonitrile complexes as a new class of highly reactive alkylation catalysts
Trost, Barry M.,Merlic, Craig A.
, p. 9590 - 9600 (2007/10/02)
A series of molybdenum complexes bearing α-diimine, N,N′-diarylideneethylenediamine, and isonitrile ligands have been prepared and evaluated for their ability to catalyze alkylations by using allyl acetates and especially allyl sulfones. (bpy)Mo(CH3
On the Regio- and Stereoselectivity of Bu4N-Catalyzed Allylic Alkylation
Xu, Yuanyao,Zhou, Bo
, p. 974 - 977 (2007/10/02)
Bu4N has been found to catalyze the alkylation of allylic carbonate with malonate anion.The reaction proceeds with good regioselectivity, the nucleophile attacking predominantly at the carbon where the leaving group was attached.Retention of configuration of the double bond during the course of reaction was observed.Alkylation of methyl (Z)-5-carbomethoxy-1-cyclohexen-3-yl carbonate with sodium salt of dimethyl malonate yielded dimethyl ((Z)-5-carbomethoxy-1-cyclohexen-3-yl)malonate in a highly stereoselective fashion, and a net retention of configuration at the center undergoing substitution is thus established.On the basis of regio- and stereochemical results, a reaction pathway involving an ?-allyliron complex has been suggested.
SUBSTITUTIONS CATALYSEES AU NICKEL D'ACETATES ET DE SULFONES ALLYLIQUES
Cuvigny, Therese,Julia, Marc
, p. 383 - 408 (2007/10/02)
The allylic substitution of stable enolates derived from diethyl malonate, ethyl cyanoacetate, ethyl benzylsulfonylacetate, bis(benzenesulfonyl)methane and sodium p-toluenesulfinate by a variety of allylic esters and sulfones has been investigated.Suitable ligands and reaction conditions have been found to ensure high yields, and in some cases considerable control of the regioselectivity of the reaction.
