52264-92-3Relevant academic research and scientific papers
Indole-Catalyzed Bromolactonization in Lipophilic Solvent: A Solid-Liquid Phase Transfer Approach
Chen, Tao,Foo, Thomas Jian Yao,Yeung, Ying-Yeung
, p. 4751 - 4755 (2015/08/18)
We have developed a novel indole-catalyzed bromolactonization of olefinic acids. The reaction could be conducted in lipophilic solvent through a solid-liquid phase transfer mechanism. This catalytic protocol has been applied to the synthesis of base-sensitive bromolactones. (Chemical Equation Presented).
Palladium-catalyzed asymmetric intermolecular Mizoroki-Heck reaction for construction of a chiral quaternary carbon center
Zhang, Qing-Song,Wan, Shi-Li,Chen, Di,Ding, Chang-Hua,Hou, Xue-Long
supporting information, p. 12235 - 12238 (2015/07/27)
Palladium-catalyzed asymmetric intermolecular Mizoroki-Heck reaction for the construction of a chiral quaternary carbon center is developed, affording 2,2-disubstituted 2,5-dihydrofurans in high yield with excellent enantioselectivity. The products are ea
Synthesis of chiral butenolides using amino-thiocarbamate-catalyzed asymmetric bromolactonization
Tan, Chong Kiat,Er, Jun Cheng,Yeung, Ying-Yeung
, p. 1243 - 1246 (2014/02/14)
The asymmetric cyclization of 4,4-disubstituted 3-butenoic acids is studied. Amino-thiocarbamates are used as the catalysts and N-bromosuccinimide is used as the stoichiometric halogen source. The resulting γ-butanolide products are readily converted into the corresponding γ-butenolides (up to 58% ee) derivatives in one-pot.
Chiral silver phosphate-catalyzed cycloisomeric kinetic resolution of α-allenic alcohols
Wang, Yan,Zheng, Kuan,Hong, Ran
, p. 4096 - 4099 (2012/04/10)
A kinetic resolution of α-allenic alcohols is realized through chiral silver phosphate-catalyzed cycloisomerization with high stereoselectivity (selectivity factor up to 189) and tolerance of a variety of functional groups. A mechanistic model is proposed to interpret the origin of the high stereoselectivity and broad substrate scope.
Enantiodivergent syntheses of γ-substituted butenolides with tertiary and quaternary asymmetric centers
Suzuki, Katsufumi,Inomata, Kohei
, p. 745 - 749 (2007/10/03)
Continuous nucleophilic addition with several organometallic reagents to tricyclic lactone (-)-1 proceeded diastereoselectively. Newly generated tertiary and quaternary asymmetric centers were controlled by the order in which the nucleophilic reagents were added. Using this methodology, enantiodivergent syntheses of several γ-substituted butenolides with tertiary and quaternary asymmetric centers were established from a single chiral material.
Lithiated 4-isopropyl-3-(methylthiomethyl)-5,5-diphenyloxazolidin-2-one: A chiral formyl anion equivalent for enantioselective preparations of 1,2-diols, 2-amino alcohols, 2-hydroxy esters, and 4-hydroxy-2-alkenoates
Gaul,Schaerer,Seebach
, p. 3059 - 3073 (2007/10/03)
The heterocyclic compound specified in the title (and readily prepared from commercial precursors) has a sterically protected C=O group, so that direct lithiation by BuLi at the exocyclic CH2 group is possible (3 → Li-3). The lithiated N,S-acetal derivative (Li-3) adds diastereoselectively to aldehydes (Table 2), unsymmetrical ketones (Table 3), chalcone (1,4-addition, Scheme 2), and N-phosphinoyl-and N-sulfonylimines (Table 4). Protection of the newly formed OH groups (Scheme 3) and/or MeS/OH displacement by Hg(O2CCF3)2 in aqueous THF/acetonitrile converts the N,S-acetals into hemiaminals (→ 20) which, in turn, are readily cleaved to aldehydes, with recovery of the chiral auxiliary (1, Scheme 4). The aldehydes (especially those lacking α-carbonyl hydrogens) may be isolated, or they are trapped in situ by reduction to (selectively protected) diols or amino alcohols, by addition of Grignard or Li reagents, which provides diols with two stereogenic centers, by oxidation to give 2-hydroxy esters, or by olefination to provide 4-hydroxy-2-alkenoates (Scheme 5). The scope and limitations of the new, overall enantioselective transformation are determined, and the readily recovered chiral auxiliary used is compared with oxazolidinones of other substitution patterns (Scheme 7). The configuration of a number of products has been assigned by single-crystal X-ray diffraction (cf. Figure 5). These structures and similarities of NMR data led to configurational assignment of the other products (see formulas in the schemes and tables) by analogy. A simple mechanistic model for the stereochemical course of the addition of Li-3 to aldehydes and ketones is presented (Figure 6).
Synthesis of Both Enantiomers of Optically Pure Saturated and α,β-Unsaturated γ-Substituted γ-Lactones from Chiral Sulphoxides. X-Ray Molecular structure of (3R,4S)-4-Methyl-4-t-butyl-3-(p-tolylthio)butanolide and of (3R,4R)-4-(Cyclohex-1-enyl)-4-methyl-3
Albinati, Alberto,Bravo, Pierfrancesco,Ganazzoli, Fabio,Resnati, Giuseppe,Viani, Fiorenza
, p. 1405 - 1416 (2007/10/02)
The lithium carbanions of optically pure (+)-(R)-p-tolyl alkyl sulphoxides (5) reacted with lithium bromoacetate and gave (+)-(R)-3-(p-tolylsulphinyl)carboxylic acids (3).Their dimetallation produced a chiral homoenolate dianion equivalent (6) which added
