89278-22-8Relevant academic research and scientific papers
Palladium-Catalyzed Arylation of Trimethylsilyl Enolates of Esters and Imides. High Functional Group Tolerance and Stereoselective Synthesis of α-Aryl Carboxylic Acid Derivatives
Liu, Xiaoxiang,Hartwig, John F.
, p. 5182 - 5191 (2004)
A general procedure for the palladium-catalyzed arylation of trimethylsilyl enolates of esters and imides is reported. In the presence of ZnF2 or Zn(O-t-Bu)2 as an additive, the trimethylsilyl enolates of esters, including those bearing α-alkoxy derivatives, underwent arylation in high yield with high functional group tolerance. This arylation chemistry was extended to ester derivatives bearing chiral auxiliaries to form new tertiary stereocenters. The arylation of imides bearing the Evans auxiliary proceeded with selectivities up to 90% de. Further, the arylation of the ketal developed by Ley provided α-aryl glycolates with excellent diastereoselectivities (90 to >98% de). This reaction provides a convenient route to the synthesis of enantiopure α-aryl-α-hydroxy esters. Reactions conducted with Zn(O-t-Bu)2 as an additive occurred at room temperature to give enhanced diastereoselectivities with both chiral reagents. Mechanistic studies showed that the reaction conditions are neutral enough that the observed diastereomeric ratios reflect kinetic selectivities.
Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide-Functionalized Phosphine Ligands
Hu, Zhiyong,Wei, Xiao-Jing,Handelmann, Jens,Seitz, Ann-Katrin,Rodstein, Ilja,Gessner, Viktoria H.,Goo?en, Lukas J.
supporting information, p. 6778 - 6783 (2021/02/01)
The coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α-aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide-functionalized phosphines to fit the requirements of Negishi couplings. Record-setting activities were achieved in palladium-catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl-YPhos ligand bearing an ortho-tolyl-substituent in the backbone. This highly electron-rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
Palladium-catalyzed α-arylation of zinc enolates of esters: Reaction conditions and substrate scope
Hama, Takuo,Ge, Shaozhong,Hartwig, John F.
, p. 8250 - 8266 (2013/09/24)
The intermolecular α-arylation of esters by palladium-catalyzed coupling of aryl bromides with zinc enolates of esters is reported. Reactions of three different types of zinc enolates have been developed. α-Arylation of esters occurs in high yields with i
Theramutein modulators
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Page/Page column 177-178, (2010/02/17)
This invention relates to agents that are inhibitors or activators of variant forms of endogenous proteins and novel methods of identifying such variants. Of particular interest are inhibitors and activators of endogenous protein variants, encoded by genes which have mutated, which variants often arise or are at least first identified as having arisen following exposure to a chemical agent which is known to be an inhibitor or activator of the corresponding unmutated endogenous protein.
COMPOUNDS FOR THE TREATMENT OF SPINAL MUSCULAR ATROPHY AND OTHER USES
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Page/Page column 11, (2009/12/27)
Compounds of Formula (I) or (II) useful for the treatment of spinal muscular atrophy or other uses, as well as methods of using such compounds to increase SMN expression, increase EAAT2 expression, or increase the expression of a nucleic acid that encodes
THERAMUTEIN MODULATORS
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Page/Page column 211, (2008/12/07)
This invention relates to agents that are inhibitors or activators of variant forms of endogenous proteins and novel methods of identifying such variants. Of particular interest are inhibitors and activators of endogenous protein variants, encoded by genes which have mutated, which variants often arise or are at least first identified as having arisen following exposure to a chemical agent which is known to be an inhibitor or activator of the corresponding unmutated endogenous protein.
Palladium-catalyzed α-arylation of esters and amides under more neutral conditions
Hama, Takuo,Liu, Xiaoxiang,Culkin, Darcy A.,Hartwig, John F.
, p. 11176 - 11177 (2007/10/03)
Two procedures for the ∞-arylation of carbonyl compounds under conditions that are more neutral than those of reactions of aryl halides with alkali metal enolates are reported. The first procedure rests upon the development of catalysts bearing the hindered pentaphenylferrocenyl di-tert-butylphosphine (Q-phos) and the highly reactive dimeric Pd(I) complex {P(t-Bu)3]PdBr}2. By this procedure, zinc enolates prepared from ∞-bromo esters and amides react with aryl halides to form ∞-aryl esters and amides in high yields under mild conditions with 1-2 mol % catalyst and with remarkable functional group tolerance. By the second procedure, silyl ketene and silyl ketimine acetals react with aryl bromides in the presence of substoichiometric zinc fluoride, 1 mol % Pd(dba)2, and 2 mol % P(t-Bu)3 in DMF solvent at 80 °C. Reactions of zinc tert-butyl acetate and propionate enolates and trimethylsilyl ketene acetals of tert-butyl propionate and methyl isobutyrate with aryl bromides bearing electron-donating and potentially reactive, base-sensitive electron-withdrawing groups and with pyridyl bromides are reported. In addition, the diastereoselective coupling of phenyl bromide with an imide enolate bearing the Evans auxiliary is reported, and this study shows that racemization of base-sensitive stereocenters does not occur during the coupling process under these more neutral conditions. Copyright
Vicarious Nucleophilic Substitution of Hydrogen in Nitroarenes with α-Substituted Nitriles and Esters. Direct α-Cyanoalkylation and α-Carbalkoxyalkylation of Nitroarenes
Makosza, Mieczyslaw,Winiarski, Jerzy
, p. 1494 - 1499 (2007/10/02)
Carbanions generated from alkanenitriles bearing α-chloro, α-OR, or α-SR groups and from aliphatic esters bearing α-SR groups react with mononitroarenes to replace hydrogen atoms of the nitroaromatic ring ortho or para to the nitro group with α-cyanoalkyl or α-carbalkoxyalkyl substituents.The nucleophilic replacement of hydrogen with such carbanions proceeds faster than substitution of halogen ortho or para to the nitro group.
