76549-03-6Relevant articles and documents
Chemistry of Enoxysilacyclobutanes. 3. Uncatalyzed, Syn-Selective, Asymmetric Aldol Additions
Denmark, Scott E.,Griedel, Brian D.
, p. 5136 - 5138 (1994)
Asymmetrically modified S,O-(alkoxysilacyclobutyl)ketene acetals derived from methane thiol esters reacted with aromatic aldehydes at low temperature to afford, after desilylation, the corresponding β-hydroxythiol ester aldolates in high enantiomeric excess (91-94percent ee).
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.
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.
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.
Synthesis of γ-Lactones via the kowalski homologation reaction: Protecting-group-free divergent total syntheses of eupomatilones-2,5,6, and 3- epi-eupomatilone-6
Choi, Hosam,Jang, Hanho,Kim, Hyoungsu,Lee, Kiyoun
, p. 7857 - 7862 (2019/10/11)
A highly efficient synthesis of functionalized chiral γ-butyrolactone scaffolds has been described. The basis of the approach is the Kowalski ester homologation that is modified for our proposed transformation. The newly developed methodology combines a d
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
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.
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
Polymer-supported PPh3 as a reusable organocatalyst for the Mukaiyama aldol and Mannich reaction
Matsukawa, Satoru,Fukazawa, Kazuki,Kimura, Junya
, p. 27780 - 27786 (2014/07/21)
An easily accessible and user-friendly polymer-supported phosphine PS-PPh3 catalyzes the aldol reaction of aldehydes and imines. A broad range of aldehydes and imines could be applied under mild conditions using 5-10 mol% PS-PPh3. PS-PPh3 was easily recovered and reused with minimal loss of activity. This journal is the Partner Organisations 2014.
Enantio- and diastereoselective hetero-Diels-Alder reactions between 4-methyl-substituted Rawal's diene and aldehydes catalyzed by chiral dirhodium(II) carboxamidates: Catalytic asymmetric synthesis of (-)-cis-aerangis lactone
Watanabe, Yudai,Shimada, Naoyuki,Anada, Masahiro,Hashimoto, Shunichi
, p. 63 - 73 (2014/02/14)
The first catalytic asymmetric hetero-Diels-Alder (HDA) reaction between 3-tert-butyldimethylsilyloxy- 1-dimethylamino-1,3-pentadiene (4-methyl-substituted Rawal's diene) and aldehydes is described. With 3 mol % of dirhodium(II) tetrakis[N-benzene-fused-p
