Article
Chemistry, Organic
Ksenia S. Stankevich, Matthew J. Cook
Summary: The Hosomi-Sakurai reaction is a crucial transformation for the creation of complex carbon-cyclic systems. These methods are capable of generating significant stereochemical complexity in a single step and have been extensively used in the total synthesis of carbon-rich natural products. This review focuses on the application of this approach in carbocyclization reactions, where the formed C-C bond is incorporated into an all-carbon cyclic system, with particular emphasis on stereochemical selectivity.
TETRAHEDRON LETTERS
(2023)
Article
Biochemistry & Molecular Biology
Zubao Gan, Deyun Cui, Hongyun Zhang, Ying Feng, Liying Huang, Yingying Gui, Lu Gao, Zhenlei Song
Summary: The Hosomi-Sakurai allylation of allylsilanes with beta,gamma-unsaturated alpha-ketoesters has been successfully catalyzed by (Ph3C)[BPh((F))(4)] to afford gamma,gamma-disubstituted alpha-ketoesters in high yields and excellent chemoselectivity. Preliminary mechanistic studies indicate that the trityl cation is the major contributor to the catalysis, with the silyl cation playing a minor role.
Article
Chemistry, Organic
Nikhil Srivastava, Hyun-Joon Ha
Summary: A straightforward and highly diastereoselective synthesis of beta-(aziridin-2-yl)-beta-hydroxy ketones was achieved via the Mukaiyama aldol reaction, with excellent yields and diastereoisomeric ratio. These ketones were further utilized in the synthesis of various alkaloids, demonstrating their versatile applications in organic synthesis.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Sota Fukasawa, Tatsuya Toyoda, Ryohei Kasahara, Chisato Nakamura, Yuuki Kikuchi, Akiko Hori, Gary J. Richards, Osamu Kitagawa
Summary: Recently, catalytic enantioselective syntheses of N-C axially chiral compounds have been reported. In this study, good enantioselectivity was achieved in the reaction of allyl acetate with secondary sulfonamides using (S,S)-Trost ligand-(allyl-PdCl)(2) catalyst, resulting in rotationally stable N-C axially chiral compounds.
Article
Chemistry, Organic
Jinping Yuan, Pankaj Jain, Jon C. Antilla
Summary: The catalytic asymmetric addition of beta,gamma-substituted allylboronates to aldehydes has been described, showing highly efficient and selective reactions.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Zhi-Yong Han, Liu-Zhu Gong
Summary: Asymmetric Bronsted acid catalysis is a powerful concept for asymmetric synthesis. Chiral bisphosphoric acids have received much attention in the last two decades due to their unique catalytic properties attributed to intramolecular hydrogen bonding interactions. Many structurally unique and effective bisphosphoric acids have been synthesized, exhibiting superior selectivity in a broad range of asymmetric transformations. This review provides an overview of chiral bisphosphoric acid catalysts and their applications in catalyzing asymmetric transformations.
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
Yiran Mo, Xuehuan Zhang, Yongqi Yao, Cong Duan, Ling Ye, Zhichuan Shi, Zhigang Zhao, Xuefeng Li
Summary: A sulfa-Michael/aldol/lactonization cascade reaction has been established to construct isotetronic acid-fused thiochromanes in a highly stereoselective fashion (>= 11:1 dr, 35-98% ee). The tricyclic products were obtained in 35-99% isolated yields in the presence of a bifunctional squaramide. Three reactive sites of beta,gamma-unsaturated alpha-ketoester, including the less-explored ester carbonyl group, were sequentially utilized to construct two fused heterocycles in a one-pot operation.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Matthew N. Grayson
Summary: Since 2004, the field of CPA catalysis has grown immensely, with Terada reporting the first example of CPA activation of aldehydes in 2008 and proposing a dual activation mode. DFT calculations have identified a lower-energy mechanism for this landmark reaction.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jia-Bin Pan, Zhi-Chun Yang, Xuan-Ge Zhang, Mao-Lin Li, Qi-Lin Zhou
Summary: Here, we present a method for enantioselective phosphoric acid catalyzed amination of ketenes generated from α-aryl-α-diazoketones. Mechanistic studies elucidated the reaction pathway and explained how the catalyst expedited the transformation and controlled the enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(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
Chemistry, Organic
Samuel Lauzon, Laurent Caron, Thierry Ollevier
Summary: This study describes a seven-step synthesis of a chiral 2,2'-bipyridinediol ligand starting from commercially available materials, with the key step being the O-2-mediated oxidative homocoupling reaction. The complexation of Fe-II with the chiral ligand showed an unusual heptacoordination and steric strain caused by the 3,3'-dimethyl groups. Furthermore, asymmetric induction using this ligand was investigated in Mukaiyama aldol and thia-Michael reactions, showing improved chiral induction compared to a catalyst made from a different ligand.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Li-Xia Liu, Yu-Qing Bai, Xiang Li, Chang-Bin Yu, Yong-Gui Zhou
Summary: Combining base-promoted retro-sulfa-Michael addition with palladium-catalyzed asymmetric allenylic alkylation, a streamlined synthesis of chiral thiochromanones containing two central chiralities (including a quaternary stereogenic center) and an axial chirality (allene unit) was successfully achieved, with yields up to 98%, dr of 49.0:1, and >99% ee.
Article
Chemistry, Multidisciplinary
Cole C. Sorensen, Frank A. Leibfarth
Summary: This study demonstrates for the first time the stereoselective cationic helix-sense-selective polymerization of a prochiral vinyl monomer, resulting in optically active helical polymers. The use of chiral counterions enables the independent control of polymer helicity and tacticity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Ruiqi Tong, Song Liu, Chen Zhao, Dongyang Jiang, Lu Gao, Wanshu Wang, Bengui Ye, Zhenlei Song
Summary: A new nonracemic reagent has been developed for the asymmetric crotylboration of aldehydes. This reaction provides compounds with high yields and excellent stereo-selectivity, showcasing its potential in the synthesis of polyketide natural products.
Article
Chemistry, Applied
Masahiro Sai
ADVANCED SYNTHESIS & CATALYSIS
(2018)
Article
Chemistry, Applied
Masahiro Sai
ADVANCED SYNTHESIS & CATALYSIS
(2018)
Article
Chemistry, Multidisciplinary
Masahiro Sai, Matsujiro Akakura, Hisashi Yamamoto
CHEMICAL COMMUNICATIONS
(2014)
Article
Chemistry, Organic
Masahiro Sai, Seijiro Matsubara
Article
Chemistry, Organic
Masahiro Sai, Seijiro Matsubara
Article
Chemistry, Applied
Masahiro Sai, Seijiro Matsubara
ADVANCED SYNTHESIS & CATALYSIS
(2019)
Article
Chemistry, Organic
Masahiro Sai
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2019)
Article
Chemistry, Applied
Masahiro Sai
Summary: The tetraarylpyrrole-based phosphine ligand L1 in combination with Pd(dba)(2) serves as an effective catalyst for the Buchwald-Hartwig amination reaction, allowing rapid coupling of a variety of amines with aryl chlorides and selective monoarylation of aliphatic primary amines under specific conditions. Comparison experiments demonstrate the superior catalytic activity of L1 in the Pd-catalyzed C-N coupling of various amines.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Masahiro Sai, Hiroaki Kurouchi
Summary: In this study, the first KHMDS-catalyzed Michael additions of allylic alcohols to alpha,beta-unsaturated amides were reported. The reaction proceeds smoothly with only 5 mol% of KHMDS to afford a variety of 1,5-ketoamides in high yields. Mechanistic investigations revealed that the in-situ generation of the enolate from the allylic alcohol through a tunneling-assisted 1,2-hydride shift is crucial for the success of this transformation.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Masahiro Sai
Summary: This study introduces a novel base-promoted reaction method for the diastereoselective synthesis of 1,3-diols with three contiguous stereogenic centers from allylic alcohols and aldehydes via allylic isomerization-initiated Aldol-Tishchenko reactions. Unlike traditional systems, this method utilizes readily available allylic alcohols as nucleophiles instead of enolizable aldehydes and ketones, offering a more sustainable and efficient approach to complex diol synthesis.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Organic
Masahiro Sai
Summary: The isomerization of allylic alcohols is an important reaction, and this paper reports the development of an efficient catalytic system that allows for the isomerization of a broad range of substrates with high yields. The catalytic system was also successfully applied to a tandem reaction.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Momoka Shimaoka, Masahiro Sai
Summary: Given the significance of Azaspirocycles in drugs and natural products, this study presents a silver-catalyzed tandem cyclization strategy that allows atom-economic synthesis of various azaoxa- and diazaspirocycles from alkynes with two appended oxygen- and nitrogen-based nucleophiles. The intramolecular attack of the pendant nucleophile on the in situ-generated iminium intermediate is crucial for the success of this transformation.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Masahiro Sai, Takatoki Mizuno
Summary: In this study, a (KOBu)-Bu-t/DMF catalytic system was developed to efficiently synthesize chalcone derivatives from propargylic alcohols bearing aryl substituents at the 1- and 3-positions. Mechanistic investigations revealed that a 1,3-hydride shift was crucial for the reaction. This method offers economic and environmental advantages as it does not involve the use of transition metals.
SYNTHETIC COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Shuto Okuda, Yutaka Narita, Rikuo Hayashi, Masahiro Sai
Summary: This paper describes the regio- and diastereoselective synthesis of unsymmetrical 1,4-diketone-derived (Z)-monosilyl enol ethers from 1-arylallyloxysilanes and Weinreb amides using (trimethylsilyl)methylpotassium as a base. The key step in this transformation is the metalation of 1-arylallyloxysilanes to generate siloxyallylpotassiums. The products can be further converted into diverse alpha-monofunctionalized unsymmetrical 1,4-diketones.
CHEMICAL COMMUNICATIONS
(2023)
