13161-18-7Relevant articles and documents
Quantum mechanical predictions of the stereoselectivities of proline-catalyzed asymmetric intermolecular aldol reactions
Bahmanyar,Houk,Martin, Harry J.,List, Benjamin
, p. 2475 - 2479 (2003)
Quantum mechanical calculations were employed to predict the ratio of four stereoisomeric products expected from two complex reactions involving the aldol reactions of cyclohexanone with benzaldehyde or with isobutyraldehyde catalyzed by (S)-proline. Expe
Solvent-effects tuning the catalytic reactivity of prolinamides in asymmetric aldol reactions
Huang, Xiang-Rong,Liu, Qi,Wang, Jing,Xiao, Jun-An,Yang, Hua
, p. 1590 - 1598 (2014)
Novel prolinamides were prepared and applied as organocatalysts in the asymmetric aldol reaction. Stable imidazolidinones were formed between prolinamides and aromatic aldehydes in organic solvents. It was found that aqueous conditions can significantly suppress the formation of the unwanted imidazolidinone intermediate and improve the catalytic activity of the prolinamides. As a consequence, high chemical yields (up to 99%) and good diastereoselectivity (up to >20:1 dr) and enantioselectivity (up to 95% ee) were achieved in 2-Me-THF or brine. This strategy could serve as a general solution to enhance the performance of prolinamides as organocatalysts.
Diastereoselective sulfur ylide promoted aldol/epoxidation
Hansen, Jeffrey A.,Smith, Colin R.,Linder, Ryan J.,Huffman, John C.
, p. 7209 - 7212 (2006)
A mixture of cyclohexanone or 4-methylcyclohexanone and an aromatic aldehyde is treated with dimethylsulfoxonium methylide to effect a tandem aldol/epoxidation reaction. The resulting product contains three or four new stereocenters but only one of the po
ERYTHRO SELECTIVE ALDOL REACTION OF α-TRICHLOROSTANNYL KETONES
Nakamura, Eiichi,Kuwajima, Isao
, p. 3347 - 3350 (1983)
The aldol reaction of α-stannyl ketones with aromatic and aliphatic aldehydes is highly (up to 95percent) erythro selective.
Stereochemistry of aldols: Configuration and conformation of aldols derived from cycloalkanones and aldehydes
Kitamura,Nakano,Miki,Okada,Noyori
, p. 8939 - 8950 (2001)
The structures of cycloalkanone-based threo and erythro aldols were investigated by systematic introduction of stereo-determining factors. The combination of single-crystal X-ray analysis and cryoscopic measurement and solution NMR and IR studies elucidat
Enantiopure cis- and trans-2-(2-Aminocyclohexyl)phenols: Effective Preparation, Solid-State Characterization, and Application in Asymmetric Organocatalysis
Tezeren, Mustafa A.,Ye?il, Tolga A.,Zorlu, Yunus,Tilki, Tahir,Ertürk, Erkan
, p. 7017 - 7032 (2018)
Effective synthesis of cis- and trans-2-(2-methoxyphenyl)cyclohexylamine as well as their multigram-scale optical resolution by diastereomeric salt formation with dibenzoyl tartaric acid have been described. Assignment of absolute configurations to the enantiomers has been made by X-ray crystallography. Starting from the resolved precursor, diverse aminoalkylphenols (AAPs) having primary, secondary, and tertiary amine group as well as a quaternary ammonium phenol have been prepared as potential bifunctional organocatalysts based on the cyclohexane backbone. We furthermore report herein that AAPs carrying a primary amine and a phenolic hydroxyl group can catalyze the direct aldol reaction with high activity and setereoselectivity, and thus up to 97 % yield, 90:10 syn/anti diastereomeric ratio, and 80 % enantiomeric excess can be achieved.
Repeated Use of the Catalyst in Ln(OTf)3-Catalyzed Aldol and Allylation Reactions
Kobayashi, Shu,Hachiya, Iwao,Yamanoi, Yoshinori
, p. 2342 - 2344 (1994)
The lanthanoide trifluoromethanesulfonate (lanthanoid triflate)-catalyzed aldol reactions of silyl enol ethers with aldehydes and allylation reactions of tetraallyltin with aldehydes proceeded smoothly in a water-ethanol-toluene system.The reactions proce
Reinvestigation of the Diastereoselectivity of Kinetic Aldol Condensation of Cyclohexanone Lithium Enolate with Benzaldehyde
Hirama, Masahiro,Noda, Takeshi,Takeishi, Shoichi,Ito, Sho
, p. 2645 - 2646 (1988)
Aldol condensation of cyclohexanone lithium enolate with benzaldehyde has been shown to give a considerably higher stereoselectivity at low temperature than that reported previously.
Environmentally benign diastereoselective synthesis of granatane and tropane aldol derivatives
Nodzewska, Aneta,Bokina, Agnieszka,Romanowska, Katarzyna,Lazny, Ryszard
, p. 29668 - 29681 (2014)
Direct aldol reactions of tropinone and granatanone (pseudopelletierine) with aromatic aldehydes were promoted by the presence of water. The anti-syn-diastereoselectivity depended on the amount of water used or on the possibility of product precipitation
Hydrophobically directed aldol reactions: Polystyrene-supported L-proline as a recyclable catalyst for direct asymmetric aldol reactions in the presence of water
Gruttadauria, Michelangelo,Giacalone, Francesco,Marculescu, Adriana Mossuto,Lo Meo, Paolo,Riela, Serena,Noto, Renato
, p. 4688 - 4698 (2007)
A simple synthetic methodology for the preparation of a polystyrene-supported L-proline material is reported, and this material has been used as catalyst in direct asymmetric aldol reactions between several ketones and arylaldehydes to furnish aldol produ
ON THE STEREOCHEMISRY OF THE ALDOL-ADDITION
Hoffmann, Reinhard W.,Ditrich, Klaus,Froech, Sybille
, p. 5517 - 5524 (1985)
NOE-experiments and STO-3G calculations suggest that E-enol borates exist in an U-conformation 7a, whereas the Z-enol borates should prefer the extended conformation 8b.These observations have been linked to the stereoselectivity of the aldol addition.The
Chiral lithium amides on solid support: Synthesis and applications in enantioselective deprotonation of cyclic ketones
Majewski, Marek,Ulaczyk, Agnieszka,Wang, Fan
, p. 8755 - 8758 (1999)
Several chiral amines attached to polymer support (Merrifield resin or a soluble analog) are described. Lithium amides, generated from these amines by treatment with BuLi, react with C(S)-symmetrical ketones to give the corresponding enolates enantioselec
Efficient Mukaiyama aldol reaction in water with TiO4 tetrahedra on a hydrophobic mesoporous silica surface
Shintaku, Hiroshi,Nakajima, Kiyotaka,Kitano, Masaaki,Hara, Michikazu
, p. 13473 - 13476 (2014)
A new heterogeneous catalyst, hydrophobic TiO4-deposited mesoporous silica, has been designed for the efficient Mukaiyama-aldol condensation, a water-participating Lewis acid-catalyzed reaction between a hydrophobic carbonyl compound and silyl
Highly diastereo- and enantioselective direct aldol reactions promoted by water-compatible organocatalysts bearing central and axial chiral elements
Peng, Fang-Zhi,Shao, Zhi-Hui,Pu, Xue-Wei,Zhang, Hong-Bin
, p. 2199 - 2204 (2008)
Two novel bifunctional primary amine catalysts 1 (RA,S,S) and 2 (RA,R,R), which bear both central and axial chiral elements, have been developed to promote highly diastereoselective and enantioselective aldol reactions of arylaldehyd
A chemo-enzymatic oxidation/aldol sequential process directly converts arylbenzyl alcohols and cyclohexanol into chiral β-hydroxy carbonyls
Cheng, Qipeng,Li, Hongyu,Liu, Guohua,Su, Yu,Tan, Chunxia,Wang, Chengyi,Wang, Yu,Xiao, Rui
supporting information, p. 7773 - 7779 (2021/10/12)
The development of a combination enzyme and organocatalyst for aqueous sequential organic transformation has great significance, in that it is not only environmentally friendly but also overcomes only a single methodological drawback, either in the chemical or biological process. Herein, through the utilization of the bulky steric hindrance of chiral proline derivatives, an integrated laccase and proline as a chemo-enzymatic co-catalyst system is developed. It enables an efficient oxidation/aldol enantioselective sequential reaction to be accomplished, overcoming the mutual deactivation issue. As we present in this study, this one-pot organic transformation, an initial laccase-mediated oxidation of arylbenzyl alcohols and cyclohexanol to form aldehydes and cyclohexanone, followed by a subsequent proline derivative-catalyzed aldol condensation of the in situ generated intermediates, provides various 1,2-diastereoisomeric chiral β-hydroxy ketones with acceptable yields and high enantio-/diastereoselectivities.
Self-assembled Polydiacetylene Nanoribbons for Semi-heterogeneous and Enantioselective Organocatalysis of Aldol Reactions in Water
Hoang, Minh-Duc,Kumar, Ramar Arun,Buisson, David A.,Ling, Wai Li,Gravel, Edmond,Doris, Eric
, p. 1156 - 1160 (2020/01/02)
We report the synthesis, characterization, and supra-molecular assembly of novel diacetylene amphiphilic units bearing a chiral proline-derived head group. In water, these amphiphiles self-assemble into twisted ribbons that are photo-polymerized to afford
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
supporting information, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
