1575-70-8Relevant articles and documents
New conditions for the generation of dianions of carboxylic acids
Brun, Eva M.,Casades, Isabel,Gil, Salvador,Mestres, Ramon,Parra, Margarita
, p. 5443 - 5446 (1998)
Lithium carboxylic acid enediolates are generated efficiently using lithium amides prepared from thienyllithium or butyllithium and either diethylamine, piperazine, N,N'-dibenzylethylenediamine, N-benzylpiperazine or 1,3,3-trimethyl-6-azabicyclo[3.2.1]oct
Intermolecular free radical reactions on solid support. Allylation of esters
Sibi, Mukund P.,Chandramouli, Sithamalli V.
, p. 8929 - 8932 (1997)
The first examples of intermolecular free radical allylation reactions on solid support are reported. The allylation proceeds in good chemical efficiency with a variety of substrates as well as allylating agents. Control experiments indicate that the polymer matrix is inert to the reaction conditions.
Dual Activation of Unsaturated Amides with Schwartz's Reagent: A Diastereoselective Access to Cyclopentanols and N,O-Dimethylcyclopentylhydroxylamines.
Coelho, Aurélien,Souvenir Zafindrajaona, Mahasoa-Salina,Vallée, Alexis,Behr, Jean-Bernard,Vasse, Jean-Luc
supporting information, (2021/12/06)
The diastereoselective access to cyclopentanols and N,O-dimethylcyclopentylhydroxylamines from 4-pentenoic acid-derived Weinreb amides is described. Based on the concomitant generation of both the nucleophilic and the electrophilic poles by hydrozirconati
Radical Aryl Migration from Boron to Carbon
Daniliuc, Constantin G.,Mück-Lichtenfeld, Christian,Studer, Armido,Wang, Dinghai
supporting information, p. 9320 - 9326 (2021/07/19)
Radical aryl migration reactions represent a unique type of organic transformations that involve the intramolecular migration of an aryl group from a carbon or heteroatom to a C- or heteroatom-centered radical through a spirocyclic intermediate. Various elements, including N, O, Si, P, S, Sn, Ge, and Se, have been reported to participate in radical aryl migrations. However, radical aryl migration from a boron center has not been reported to date. In this communication, radical 1,5-aryl migration from boron to carbon in aryl boronate complexes is presented. C-radicals readily generated through radical addition onto alkenyl aryl boronate complexes are shown to engage in 1,5-aryl migration reactions to provide 4-aryl-alkylboronic esters. As boronate complexes can be generatedin situby the reaction of alkenylboronic acid esters with aryl lithium reagents, the aryl moiety is readily varied, providing access to a series of arylated products starting from the same alkenylboronic acid ester via divergent chemistry. Reactions proceed with high diastereoselectivity under mild conditions, and also the analogous 1,4-aryl shifts are feasible. The suggested mechanism is supported by DFT calculations.
Photoinduced Copper-Catalyzed Asymmetric Decarboxylative Alkynylation with Terminal Alkynes
Dong, Xiao-Yang,Du, Xuan-Yi,Fang, Jia-Heng,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Xin-Yuan,Wang, Li-Lei,Xia, Hai-Dong
supporting information, p. 16926 - 16932 (2020/08/25)
We describe a photoinduced copper-catalyzed asymmetric radical decarboxylative alkynylation of bench-stable N-hydroxyphthalimide(NHP)-type esters of racemic alkyl carboxylic acids with terminal alkynes, which provides a flexible platform for the construction of chiral C(sp3)?C(sp) bonds. Critical to the success of this process are not only the use of the copper catalyst as a dual photo- and cross-coupling catalyst but also tuning of the NHP-type esters to inhibit the facile homodimerization of the alkyl radical and terminal alkyne, respectively. Owing to the use of stable and easily available NHP-type esters, the reaction features a broader substrate scope compared with reactions using the alkyl halide counterparts, covering (hetero)benzyl-, allyl-, and aminocarbonyl-substituted carboxylic acid derivatives, and (hetero)aryl and alkyl as well as silyl alkynes, thus providing a vital complementary approach to the previously reported method.
Isothiourea-Catalyzed Acylative Kinetic Resolution of Tertiary α-Hydroxy Esters
Greenhalgh, Mark D.,Laina-Martín, Víctor,Neyyappadath, Rifahath M.,Qu, Shen,Smith, Andrew D.,Smith, Samuel M.
supporting information, p. 16572 - 16578 (2020/09/09)
A highly enantioselective isothiourea-catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently-developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous-flow process using a polymer-supported variant of the catalyst.
Synthesis of 5-[(Pentafluorosulfanyl)methyl]-γ-butyrolactones via a Silver-Promoted Intramolecular Cyclization Reaction
Roudias, Majdouline,Gilbert, Audrey,Paquin, Jean-Fran?ois
, p. 6655 - 6665 (2019/11/03)
The synthesis of 5-[(pentafluorosulfanyl)methyl]-γ-butyrolactones bearing different substituents at position 3 or 4 is reported. A silver-promoted intramolecular cyclization of substituted 4-chloro-5-(pentafluorosulfanyl)pentanoic acids allows the preparation of the substituted SF5-containing γ-butyrolactones in up to 96 % yield.
Copper(II)-Catalyzed Alkene Aminosulfonylation with Sodium Sulfinates for the Synthesis of Sulfonylated Pyrrolidones
Rao, Wei-Hao,Jiang, Li-Li,Liu, Xiao-Meng,Chen, Mei-Jun,Chen, Fang-Yuan,Jiang, Xin,Zhao, Jin-Xiao,Zou, Guo-Dong,Zhou, Yu-Qiang,Tang, Lin
supporting information, p. 2890 - 2893 (2019/04/30)
A copper-catalyzed direct aminosulfonylation of unactivated alkenes with sodium sulfinates for the efficient synthesis of sulfonylated pyrrolidones is described. This reaction features good functional group tolerance and wide substrate scope, providing an efficient and straightforward protocol to access this kind of pyrrolidones. Moreover, preliminary mechanistic investigations disclosed that a free-radical pathway might be invovled in the process.
Studies on the Synthesis of Endocyclic Enol Lactones via a RCM of Selected Vinyl Esters
Brodzka, Anna,Borys, Filip,Koszelewski, Dominik,Ostaszewski, Ryszard
, p. 8655 - 8661 (2018/06/22)
The novel and efficient approach toward the synthesis of endocyclic enol lactones was devised based on ring-closing metathesis of unsaturated carboxylic acids vinyl esters. Systematic studies revealed that vinyl esters are suitable substrates for RCM reaction. The developed methodology offers an easy route for synthetically challenging target molecules with different functional groups and substitution. We have also demonstrated that vinyl esters of cyclic carboxylic acids can be successfully applied for domino ring-opening ring-closing metathesis sequences.
New Strategy for Forging Contiguous Quaternary Carbon Centers via H 2 O 2 -Mediated Ring Contraction
Hu, Jiadong,Yu, Xin,Xie, Weiqing
, p. 2517 - 2524 (2017/09/28)
Stereospecific construction of contiguous quaternary carbon centers constitutes a major challenge in natural product synthesis. A general protocol that enables stereospecific construction of all stereoisomers of such a moiety remains elusive. In this article, we will discuss the oxidative ring contraction of all-substituted cyclic α-formyl ketones mediated by H 2 O 2, which provides a facile access to the stereospecific construction of contiguous quaternary carbon centers.