103979-23-3Relevant academic research and scientific papers
γ-Selective allylic substitution reaction with Grignard reagents catalyzed by copper N-heterocyclic carbene complexes and its application to enantioselective synthesis
Tominaga, Satoshi,Oi, Yukinao,Kato, Toshio,An, Duk Keun,Okamoto, Sentaro
, p. 5585 - 5588 (2004)
The reaction of allylic compounds with alkyl Grignard reagents in the presence of a catalytic amount of copper N-heterocyclic carbene (NHC) complexes proceeded predominantly in an SN2′ reaction pathway to give γ-substituted product in excellent
Allylic substitution reactions with Grignard reagents catalyzed by imidazolium and 4,5-dihydroimidazolium carbene-CuCl complexes
Okamoto, Sentaro,Tominaga, Satoshi,Saino, Naoko,Kase, Kouki,Shimoda, Kentaro
, p. 6001 - 6007 (2005)
Imidazolium and 4,5-dihydroimidazolium carbene-CuCl complexes effectively catalyzed the substitution reaction of allylic compounds with Grignard reagents in an SN2′-selective fashion. It was noteworthy that the amount of the imidazolium carbene
Short synthesis of chiral 4-substituted (S)-imidazolinium salts bearing sulfonates and their use in γ-selective reactions of allylic halides with grignard reagents
Latham, Christopher M.,Blake, Alexander J.,Lewis, William,Lawrence, Matthew,Woodward, Simon
supporting information; experimental part, p. 699 - 707 (2012/03/11)
A one-pot reaction of Boc-protected amino alcohols and 2-sulfobenzoic anhydride followed by the addition of a wide variety of primary amines has allowed rapid access to diverse libraries of amidosulfonates 1,2-C 6H4(SO3su
Regio- and enantiospecific rhodium-catalyzed arylation of unsymmetrical fluorinated acyclic allylic carbonates: Inversion of absolute configuration
Evans, P. Andrew,Uraguchi, Daisuke
, p. 7158 - 7159 (2007/10/03)
The transition metal-catalyzed allylic substitution with unstabilized carbon nucleophiles represents an important cross-coupling reaction for the construction of ternary carbon stereogenic centers. We have developed a new regio- and enantiospecific rhodium-catalyzed allylic alkylation of acyclic unsymmetrical chiral nonracemic allylic alcohol derivatives with aryl zinc bromides. This study demonstrates that the hydrotris(pyrazolyl)borate rhodium catalyst and zinc(II) halide salt are crucial for efficiency, while the addition of lithium bromide to the catalyst is necessary for obtaining optimal regiospecificity. The stereochemical course of this reaction was established through the synthesis of (S)-ibuprofen, which demonstrated that the alkylation proceeds with net inversion of absolute configuration consistent with direct addition of the nucleophile to the metal center followed by reductive elimination. Copyright
Copper-mediated regio- and enantio-selective cross-coupling of heterocyclic allyl sulphides with organomagnesium compounds: A case of 1,7-relative stereogenesis
Calo, Vincenzo,Nacci, Angelo,Fiandanese, Vito
, p. 10799 - 10810 (2007/10/03)
Optically active heterocyclic allyl sulphides 1-7 react with organomagnesium compounds in the presence of CuBr to afford optically active alkenes in good yields and very high γ-selectivity. The regioselectivity depends on the solvent as well on the CuBr: allylic sulphide ratio. The heterocyclic nucleus imparts asymmetric induction in the range of 50-98% ee. The regio- and enantio-selectivity of these reactions would be related to the coordination exerted by the heterocyclic nitrogen toward the copper organyl.
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.
Protonation and Alkykation of 1-Arylpropenyl-lithium
Tanaka, Jiro,Nojima, Masatomo,Kusabayashi, Shigekazu,Nagase, Shigeru
, p. 673 - 678 (2007/10/02)
The protonation and alkylation of 1-arylpropenyl-lithium (1a-c) in ether was undertaken systematically; the regio- and stereo-chemistry being influenced by various factors.The characteristic features are as follows. (a) Protonation occurs predominantly at C-3, whereas the sterically more crowded C-1 is the more favoured site for alkylation, and (b) although 1-arylpropenyl-lithium (1) seems to exist mainly as the E-isomer, in some cases the product (3) or (5) having the Z-configuration is produced from attack at C-3 in a significant amount together with the E-isomer, e.g. protonation by oxygen acids in the presence or absence of tetramethylethylenediamine and methylation of the p-methoxy derivative (1a).
Reaction of 1-Aryl-3-chloropropenes with Grignard Reagents. Nucleophilic Substitution versus Single-electron Transfer
Muraoka, Kiyoshige,Nojima, Masatomo,Kusabayashi, Shigekazu,Nagase, Shigeru
, p. 761 - 768 (2007/10/02)
The reactions of ambident 1-aryl-3-chloropropenes (1a-e) with a series of Grignard reagents, R'MgY (R' = Me, Pr, Ph, Pri, But; Y = Br, I), were carried out in diethyl ether (EE) and tetrahydrofuran (THF).The products were a mixture of two alkylation products (2) and (3), and three dimerization products (4)-(6).The alkylation:dimerization ratio and the composition of the two alkylation products were a marked function of substituent electronic effects in the chlorides (1a-e), R' or Y of R'MgY, and solvent.On the basis of the stereochemistry of alkylation, cyclizable probe experiments, and the effect of the addition of FeCl3 on product composition, the following conclusions were obtained.First, dimers (4)-(6) are most likely to be produced by a mechanism involving single-electron transfer (SET).Second, for the formation of alkylation products (2) and (3), three alternative pathways contribute depending on the nature of R'MgY and solvent, (a) competitive SN2-SN2' pathways in the reaction of R'MgBr in EE, (b) a process involving SET in the reaction with R'MgI in EE, and (c) SN2 pathways in the reaction of R'MgBr in THF.
