Article
Chemistry, Physical
Chonglong Li, Jihai Wang, Huiyun Ding
Summary: The novel helical poly(phenyl isocyanide) showed high optical activity in asymmetric aldol reaction and exhibited enhanced stereoselectivity compared to small molecule l-proline. The helical polymer catalysts can be easily recovered and reused for at least five cycles with maintained activity and stereoselectivity.
Article
Chemistry, Organic
Santanu Mondal, Ravindra D. Aher, Venkati Bethi, Yu-Ju Lin, Tohru Taniguchi, Kenji Monde, Fujie Tanaka
Summary: This study reports amine-based catalyst systems for the enantioselective Mannich reactions of pyruvates as nucleophiles. The reactions of pyruvates and cyclic sulfonylimines yielded the desired Mannich products, including those with tetrasubstituted carbon centers, in high yields and enantioselectivities. The choice of acid in the amine-based catalyst system played a key role in the formation of Mannich products with high enantioselectivities.
Article
Chemistry, Multidisciplinary
Stuart C. D. Kennington, Saul F. Teloxa, Miguel Mellado-Hidalgo, Oriol Galeote, Sabrina Puddu, Marina Bellido, Pedro Romea, Felix Urpi, Gabriel Aullon, Merce Font-Bardia
Summary: A direct and asymmetric aldol reaction of N-acyl thiazinanethiones with aromatic aldehydes catalyzed by chiral nickel(II) complexes was reported. The reaction gives high yields of O-TIPS-protected anti-aldol adducts with remarkable stereocontrol and atom economy. The removal of the achiral scaffold provides enantiomerically pure intermediates with synthetic interest for producing anti-alpha-amino-beta-hydroxy and alpha,beta-dihydroxy carboxylic derivatives, with theoretical calculations explaining the observed high stereocontrol.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Ryoga Hikawa, Mio Shimogaki, Taichi Kano
Summary: Novel threonine-derived amino sulfonamide organocatalysts were developed and successfully applied to asymmetric aldol reactions. The reactions produced anti-aldol adducts with high diastereo- and enantioselectivity when catalyzed by threonine-derived tosylamide, and syn-aldol adducts were obtained when using threonine-derived triflamide catalyst in reactions between alpha-siloxyacetone and aromatic aldehydes. In both cases, a significant improvement in diastereoselectivity was observed compared to threonine-derived carboxylic acid catalyst.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yujiro Hayashi
Summary: The aldol reaction is a significant carbon-carbon bond-forming reaction in organic chemistry. The use of trifluoromethyl-substituted diarylprolinol as an organocatalyst has been found to be effective in promoting cross-aldol reactions with excellent selectivities.
Article
Chemistry, Organic
Shinya Adachi, Akira Saito, Masakatsu Shibasaki
Summary: This study reports a method for direct catalytic asymmetric reactions of alkylnitriles and imines. By adding specific catalysts and additives, high yields, high anti/syn diastereoselectivities, and high enantiomeric ratios can be achieved.
Article
Chemistry, Organic
Li Hui, Yin Liang
Summary: Vinylogous reaction is an efficient tool to introduce new functional groups at the gamma-position or more remote positions of the parent functional group. The resulting highly functionalized structures are widely present in natural products, biologically active compounds, and pharmaceuticals, and serve as important synthetic intermediates. The focus of our group is the development of efficient direct vinylogous reactions using copper catalysts, particularly in the catalytic asymmetric variants.
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yuvraj Garg, James Osborne, Serhii Vasylevskyi, Nivedha Velmurugan, Fujie Tanaka
Summary: 1,3-Diamine-derived catalysts were synthesized and utilized in asymmetric Mannich reactions of ketones. The Mannich products with high enantioselectivities were obtained under mild conditions through catalysis by one of the 1,3-diamine derivatives in the presence of acids. Bond formation primarily occurred at the less-substituted α-position of the ketone carbonyl group. The primary and tertiary amines of the 1,3-diamine derivative cooperatively acted for the catalysis.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Masaru Kondo, Kento Nakamura, Chandu G. Krishnan, Hiroaki Sasai, Shinobu Takizawa
Summary: This study presents recent advances in photoswitchable chiral organocatalysts and their applications in the photomodulation of enantioselective reactions. Under appropriate light irradiation, the E/Z-photoisomerization of the photoresponsive units on the catalysts controls the catalytic activity and/or selectivity of the reactions. The study also elucidates the design, synthesis, and catalytic application of azobenzene BINOL-based photoswitchable chiral phase-transfer catalysts. This account provides insights into the appropriate design of a photoswitchable chiral organocatalyst for achieving good enantioselectivity and photocontrol.
Article
Engineering, Environmental
Celine Demeese, Clara Lods, David-Alexandre Buisson, Edmond Gravel, Irishi N. N. Namboothiri, Eric Doris
Summary: A proline analog assembled on carbon nanotubes was utilized as a heterogenized catalyst in asymmetric aldol reactions, showing high efficiency, good enantioselectivity, and sustainability using pure water as the solvent. The catalyst operates with low loadings and can be recycled without loss of performance, resulting in aldol products with yields up to 99% and enantiomeric excesses up to 98%.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Saul F. Teloxa, Miguel Mellado-Hidalgo, Stuart C. D. Kennington, Pedro Romea, Felix Urpi, Gabriel Aullon, Merce Font-Bardia
Summary: A direct and asymmetric aldol reaction between N-azidoacetyl-1,3-thiazolidine-2-thione and aromatic aldehydes catalyzed by a chiral nickel(II)-Tol-BINAP complex has been developed. The reaction gives anti alpha-azido-beta-silyloxy adducts with excellent stereocontrol and high yields. The removal of thiazolidinethione allows for the synthesis of a wide array of enantiomerically pure derivatives, providing a new route to di- and tripeptide blocks containing a beta-aryl-beta-hydroxy-alpha-amino acid.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Hyoung Min Yeo, Sungmin Kang, Taek Hyeon Kim
Summary: The first chiral proline amide-isothiouronium based bifunctional organocatalyst was developed, showing high to quantitative yields in aldol products with excellent control performance of diastereoselectivities and enantioselectivity.
TETRAHEDRON LETTERS
(2021)
Article
Chemistry, Organic
Dattatraya N. Bhangare, Rohit G. Shinde, Pushpalata D. Pawar, Milind D. Nikalje, Mahendra N. Lokhande
Summary: This method utilizes Sc(OTf)(3) as a catalyst and (-)-menthol as a chiral auxiliary to achieve remarkable diastereoselectivity in the asymmetric aldol reaction. It offers mild reaction conditions, high yields, and excellent diastereoselectivity with a variety of substituted aromatic aldehydes. Sc(OTf)(3) demonstrates excellent diastereoselectivity at -45 degrees C under different reaction conditions.
JOURNAL OF HETEROCYCLIC CHEMISTRY
(2021)
Review
Chemistry, Physical
Nilanjana Majumdar
Summary: Catalytic asymmetric transformation is a powerful strategy for synthesizing diverse nonracemic molecular entities. Carboxylic acids have been explored as building blocks in this area, and significant advancements have been made in the last three decades. They can act as both C- and O-nucleophiles, as well as electrophiles, in asymmetric reactions under catalytic conditions.
Article
Chemistry, Multidisciplinary
Ingolf Harden, Frank Neese, Giovanni Bistoni
Summary: The formation of Bronsted acid aggregates in asymmetric organocatalytic reactions has a significant impact on the stereo-controlling factors of the transformations. This study uses high-level quantum mechanical calculations to investigate the influence of catalyst structure and reaction conditions on the spontaneity of the aggregation process, shedding light on its importance.
Article
Chemistry, Organic
Geeta Devi Yadav, Pooja Chaudhary, Balaram Pani, Surendra Singh
Summary: Chiral transition metal complexes with privileged ligands are efficient catalysts for various asymmetric organic transformations. Transition metal complexes of C1-symmetric pyrrolidine-based ligands have been widely used in asymmetric organic reactions. However, a comprehensive review article on the transition metal complexes of chiral C1-symmetric pyrrolidine-based ligands derived from (L)-proline has not been published.
TETRAHEDRON LETTERS
(2024)
