76549-05-8Relevant academic research and scientific papers
Copper-Catalyzed Enantioselective Reductive Aldol Reaction of α,β-Unsaturated Carboxylic Acids to Alkyl Aryl Ketones: Silanes as Activator and Transient Protecting Group
Suzuki, Hirotsugu,Yoneoka, Kenji,Kondo, Sora,Matsuda, Takanori
supporting information, (2022/01/26)
The first enantioselective reductive aldol reaction of unprotected α,β-unsaturated carboxylic acids was developed by employing a copper/bisphosphine catalyst. The reaction features in situ protection and activation of an α,β-unsaturated carboxylic acid by a hydrosilane. The copper enolate formed in situ reacts with an alkyl aryl ketone to afford the β-hydroxy carboxylic acid with excellent enantioselectivity (up to 99 % ee). The corresponding gram-scale reaction with a low catalyst loading and the derivatization of the β-hydroxy carboxylic acids highlight the practicality of this transformation.
Visible-Light-Driven, Metal-Free Divergent Difunctionalization of Alkenes Using Alkyl Formates
Zheng, Ming,Hou, Jing,Zhan, Le-Wu,Huang, Yan,Chen, Ling,Hua, Li-Li,Li, Yan,Tang, Wan-Ying,Li, Bin-Dong
, p. 542 - 553 (2021/01/14)
In recent decades, difunctionalization of alkenes has received considerable attention as an efficient and straightforward way to increase molecular complexity. However, examples of the difunctionalization of alkenes initiated by the intermolecular addition of alkoxycarbonyl radicals providing substituted alkanoates are still rare. Herein, we present the visible light-driven metal-free divergent difunctionalization of alkenes triggered by the intermolecular addition of alkoxycarbonyl radicals under ambient conditions. Employing alkyl formates as precursors of alkoxycarbonyl radicals and 4CzIPN as the photocatalyst, a variety of substituted alkanoates, including β-alkoxy, β-hydroxy, β-dimethoxymethoxy, and β-formyloxy alkanoates, could be facilely accessed with high functional group tolerance and high efficiency. Moreover, the mechanism study revealed that β-hydroxy alkanoates were generated by a selective decomposition of orthoformates promoted by the N-alkoxyazinium salt.
Fe-Catalyzed Anaerobic Mukaiyama-Type Hydration of Alkenes using Nitroarenes
Bhunia, Anup,Bergander, Klaus,Daniliuc, Constantin Gabriel,Studer, Armido
supporting information, p. 8313 - 8320 (2021/03/08)
Hydration of alkenes using first row transition metals (Fe, Co, Mn) under oxygen atmosphere (Mukaiyama-type hydration) is highly practical for alkene functionalization in complex synthesis. Different hydration protocols have been developed, however, control of the stereoselectivity remains a challenge. Herein, highly diastereoselective Fe-catalyzed anaerobic Markovnikov-selective hydration of alkenes using nitroarenes as oxygenation reagents is reported. The nitro moiety is not well explored in radical chemistry and nitroarenes are known to suppress free radical processes. Our findings show the potential of cheap nitroarenes as oxygen donors in radical transformations. Secondary and tertiary alcohols were prepared with excellent Markovnikov-selectivity. The method features large functional group tolerance and is also applicable for late-stage chemical functionalization. The anaerobic protocol outperforms existing hydration methodology in terms of reaction efficiency and selectivity.
Siloxy Esters as Traceless Activators of Carboxylic Acids: Boron-Catalyzed Chemoselective Asymmetric Aldol Reaction**
Fujita, Taiki,Kanai, Motomu,Mitsunuma, Harunobu,Sameera, W. M. C.,Yamane, Mina
supporting information, p. 24598 - 24604 (2021/10/14)
The catalytic asymmetric aldol reaction is among the most useful reactions in organic synthesis. Despite the existence of many prominent reports, however, the late-stage, chemoselective, catalytic, asymmetric aldol reaction of multifunctional substrates is still difficult to achieve. Herein, we identified that in situ pre-conversion of carboxylic acids to siloxy esters facilitated the boron-catalyzed direct aldol reaction, leading to the development of carboxylic acid-selective, catalytic, asymmetric aldol reaction applicable to multifunctional substrates. Combining experimental and computational studies rationalized the reaction mechanism and led to the proposal of Si/B enediolates as the active species. The silyl ester formation facilitated both enolization and catalyst turnover by acidifying the α-proton of substrates and attenuating poisonous Lewis bases to the boron catalyst.
Direct Catalytic Asymmetric Aldol Reaction of α-Alkylamides
Liu, Zijian,Takeuchi, Toshifumi,Pluta, Roman,Arteaga Arteaga, Fernando,Kumagai, Naoya,Shibasaki, Masakatsu
, p. 710 - 713 (2017/02/10)
A catalytic asymmetric aldol reaction directly employing amides as latent enolates has remained elusive because of the resistance of amides to enolization. A direct aldol reaction of α-alkylamides without any electron-withdrawing group harnessed by specif
Asymmetric solution-phase mixture aldol reaction using oligomeric ethylene glycol tagged chiral oxazolidinones
Turkyilmaz, Serhan,Wilcox, Craig S.
supporting information, p. 2031 - 2033 (2017/05/04)
Sorting tags are oligomeric structures that can be used as protecting groups or chiral auxiliaries enabling solution-phase mixture syntheses of multiple tagged compounds in one pot and allowing for facile and predictable chromatographic separation of products at the end of synthetic sequences. Perfluorinated hydrocarbon and oligomeric ethylene glycol (OEG) derivatives are known classes of sorting tags. Herein we describe the preparation of OEGylated chiral oxazolidinones and their use in asymmetric solution-phase mixture aldol reactions. Through the use of such oxazolidinones based on tyrosine four different individually tagged aldol adducts were obtained as a mixture, chromatographically demixed, detagged, and it was shown that these processes gave the desired aldol products in good yield and enantioselectivity.
Stereoselective Construction of Entire Diastereomeric Stereotetrads Based on an Asymmetric Morita–Baylis–Hillman Reaction
Yoshimura, Hikaru,Ishihara, Jun,Hatakeyama, Susumi
, p. 2719 - 2729 (2017/05/29)
A method for the enantio- and diastereoselective construction of all possible stereoisomers of a polypropionate stereotetrad having four contiguous stereogenic centers has been developed. The approach features an iterative sequence of cinchona-alkaloid-ca
Bioreduction of α-Acetoxymethyl Enones: Proposal for an SN2′ Mechanism Catalyzed by Enereductase
Paula, Bruno R. S.,Zampieri, Davila,Rodrigues, J. Augusto R.,Moran, Paulo J. S.
, p. 3555 - 3571 (2016/11/25)
(Z)-3-Acetoxymethyl-4-R-3-buten-2-ones (R=aryl, alkyl) and (Z)-3-methyl-4-R-3-buten-2-ones (R=aryl) were synthesized and submitted to reduction by the yeast Saccharomyces cerevisiae producing the (R)- and (S)-4-R-3-methybutan-2-ones, respectively. This stereochemistry control strategy was applied in the syntheses of (R)- and (S)-Tropional with moderate to high enantiomeric excesses. Other (Z)-3-acyloxymethyl-4-phenyl-3-buten-2-ones showed similar behavior to the (Z)-3-acetoxymethyl counterpart, and the acylated Morita–Baylis–Hillman adduct 1-acetoxy-2-methylene-1-phenylbutan-3-one produced a mixture of products, with and without the acetoxy group, via three different reaction pathways. In addition to experiments employing whole cells, those in which isolated enereductases were used suggested that the main pathway through which the loss of the acetoxy group occurs during the biocatalytic cascade is an SN2′-type reaction, rather than formal hydrogen addition followed by acetic acid elimination. Finally, related ethyl enones were reduced enantioselectively by the yeast Candida albicans, producing both (R)- and (S)-reduction products, depending on the presence of the acetoxy group in the starting material. (Figure presented.).
A study on the AMACR catalysed elimination reaction and its application to inhibitor testing
Yevglevskis, Maksims,Lee, Guat L.,Sun, Jenny,Zhou, Shiyi,Sun, Xiaolong,Kociok-K?hn, Gabriele,James, Tony D.,Woodman, Timothy J.,Lloyd, Matthew D.
, p. 612 - 622 (2016/01/12)
α-Methylacyl-CoA racemase (AMACR; P504S) catalyses a key step in the degradation of branched-chain fatty acids and is important for the pharmacological activation of Ibuprofen and related drugs. Levels of AMACR are increased in prostate and other cancers,
Asymmetric reductive aldol-type reaction with carbonyl compounds using dialkyl tartrate as a chiral ligand
Isoda, Motoyuki,Sato, Kazuyuki,Tokura, Yoriko,Tarui, Atsushi,Omote, Masaaki,Ando, Akira
, p. 956 - 961 (2014/12/11)
An asymmetric reductive aldol-type reaction of α,β-unsaturated esters with carbonyl compounds using Rh catalyst and Et2Zn was investigated. A chiral zinc complex from α,β-unsaturated ester was easily generated as the key intermediate from Et2Zn and Wilkin
