The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Rongbiao Tong - One of the best experts on this subject based on the ideXlab platform.
-
Fenton Chemistry for Achmatowicz Rearrangement
ACS Catalysis, 2021Co-Authors: Guodong Zhao, Lixin Liang, Eryu Wang, Rongbiao TongAbstract:Achmatowicz Rearrangement (AchR) is a very important transformation for the synthesis of various heterocyclic building blocks and natural products. Here, the discovery of Fenton chemistry for AchR ...
-
C-Aryl Glycosylation: Palladium-Catalyzed Aryl–Allyl Coupling of Achmatowicz Rearrangement Products with Arylboronic Acids
The Journal of organic chemistry, 2020Co-Authors: Ming Wai Liaw, Wai Fung Cheng, Rongbiao TongAbstract:The first Pd-catalyzed arylation of Achmatowicz Rearrangement products with arylboronic acids under mild conditions (rt) to provide the synthetically versatile C-aryl dihydropyranones is reported. It is found that the 4-keto group of Achmatowicz products is essential to increase the reactivity of the Pd-π-allyl complex toward arylboronic acids and that phosphine as the palladium ligand would be destructive to the reaction. This new coupling method addresses the major limitations of previous Pd-catalyzed allyl-aryl couplings of 2,3-unsaturated glycosides with an aryl Grignard or aryl zinc reagent.
-
c aryl glycosylation palladium catalyzed aryl allyl coupling of Achmatowicz Rearrangement products with arylboronic acids
Journal of Organic Chemistry, 2020Co-Authors: Ming Wai Liaw, Wai Fung Cheng, Rongbiao TongAbstract:The first Pd-catalyzed arylation of Achmatowicz Rearrangement products with arylboronic acids under mild conditions (rt) to provide the synthetically versatile C-aryl dihydropyranones is reported. It is found that the 4-keto group of Achmatowicz products is essential to increase the reactivity of the Pd-π-allyl complex toward arylboronic acids and that phosphine as the palladium ligand would be destructive to the reaction. This new coupling method addresses the major limitations of previous Pd-catalyzed allyl-aryl couplings of 2,3-unsaturated glycosides with an aryl Grignard or aryl zinc reagent.
-
Synthesis of 2-Arylpiperidines via Pd-Catalyzed Arylation of Aza-Achmatowicz Rearrangement Products with Arylboronic Acids.
Organic letters, 2019Co-Authors: Guodong Zhao, Daniel P. Canterbury, Alexandria P. Taylor, Xiayun Cheng, Peter Mikochik, Scott W. Bagley, Rongbiao TongAbstract:The first Pd-catalyzed arylation of aza-Achmatowicz Rearrangement products with arylboronic acids is achieved, providing versatile 2-aryldihydropyridinones for facile synthesis of highly functionalized 2-arylpiperidines. Key to this arylation is the use of non-phosphine-ligand palladium precatalyst. The substrate scope is demonstrated with >26 examples, and the utility of 2-aryldihydropyridinones is illustrated by the synthesis of a small collection of 2-arylpiperidines with substituents or functional groups at any carbon (C2-C6) as well as two NK1 receptor antagonists (+)-CP-999,94 and (+)-L-733,060.
-
silica gel enables Achmatowicz Rearrangement with kbr oxone under anhydrous condition for one pot functionalization
Tetrahedron, 2019Co-Authors: Guodong Zhao, Rongbiao TongAbstract:Abstract Silica gel was found to effectively promote Achmatowicz Rearrangement (AchR) using KBr/oxone under near anhydrous condition. This new protocol allows direct functionalization of AchR products in a one-pot manner, effectively reducing the cost, time, and environmental impacts derived from the conventional stop-and-go approach using separate reaction vessels. These advantages were demonstrated in four types of sequential one-pot reactions: i) AchR-Kishi reduction (and AchR-Ferrier allylation); ii) AchR-acylation-O-glycosylation; iii) AchR-acylation-[5 + 2]-cycloaddition; and iv) AchR-TEMPO oxidation.
Fernando Coelho - One of the best experts on this subject based on the ideXlab platform.
-
Sequential Morita—Baylis—Hillman/Achmatowicz Reactions: An Expeditious Access to Pyran‐3(6H)‐ones with a Unique Substitution Pattern.
ChemInform, 2016Co-Authors: Bruno Boni Guidotti, Fernando CoelhoAbstract:Abstract We herein disclosed a novel approach to synthesize densely functionalized 6-hydroxy-2 H -pyran-3(6 H )-ones with moderate to good diastereoselectivity. The method is based on a two step sequence using Morita–Baylis–Hillman adducts as substrates for the Achmatowicz Rearrangement, allowing the preparation of highly substituted pyran-3-ones with overall yields ranging from 17% to 80% and a unique substitution pattern.
-
sequential morita baylis hillman Achmatowicz reactions an expeditious access to pyran 3 6h ones with a unique substitution pattern
Tetrahedron Letters, 2015Co-Authors: Bruno Boni Guidotti, Fernando CoelhoAbstract:Abstract We herein disclosed a novel approach to synthesize densely functionalized 6-hydroxy-2 H -pyran-3(6 H )-ones with moderate to good diastereoselectivity. The method is based on a two step sequence using Morita–Baylis–Hillman adducts as substrates for the Achmatowicz Rearrangement, allowing the preparation of highly substituted pyran-3-ones with overall yields ranging from 17% to 80% and a unique substitution pattern.
-
Sequential Morita-Baylis-Hillman/Achmatowicz reactions: an expeditious access to pyran-3(6H)-ones with a unique substitution pattern
Tetrahedron Letters, 2015Co-Authors: Bruno Boni Guidotti, Fernando CoelhoAbstract:Abstract We herein disclosed a novel approach to synthesize densely functionalized 6-hydroxy-2 H -pyran-3(6 H )-ones with moderate to good diastereoselectivity. The method is based on a two step sequence using Morita–Baylis–Hillman adducts as substrates for the Achmatowicz Rearrangement, allowing the preparation of highly substituted pyran-3-ones with overall yields ranging from 17% to 80% and a unique substitution pattern.
Pabbaraja Srihari - One of the best experts on this subject based on the ideXlab platform.
-
A unified strategy for the synthesis of the C1–C14 fragment of marinolic acids, mupirocins, pseudomonic acids and thiomarinols: total synthesis of pseudomonic acid methyl monate C
Organic and Biomolecular Chemistry, 2014Co-Authors: Y. Sridhar, Pabbaraja SrihariAbstract:A flexible stereoselective approach to the common C1–C14 skeleton present in natural products of the pseudomonic acid family is described. The strategy has been extended and the total synthesis of pseudomonic acid methyl monate C was achieved. The key synthetic reactions utilized include Achmatowicz Rearrangement, Johnson–Claisen Rearrangement, Julia–Kocienski olefination, and Horner–Wadsworth–Emmons olefination reaction.
-
A unified strategy for the synthesis of the C1-C14 fragment of marinolic acids, mupirocins, pseudomonic acids and thiomarinols: total synthesis of pseudomonic acid methyl monate C.
Organic & biomolecular chemistry, 2014Co-Authors: Y. Sridhar, Pabbaraja SrihariAbstract:A flexible stereoselective approach to the common C1–C14 skeleton present in natural products of the pseudomonic acid family is described. The strategy has been extended and the total synthesis of pseudomonic acid methyl monate C was achieved. The key synthetic reactions utilized include Achmatowicz Rearrangement, Johnson–Claisen Rearrangement, Julia–Kocienski olefination, and Horner–Wadsworth–Emmons olefination reaction.
-
Stereodivergent Total Synthesis of (+)-Aspergillide B and (+)-7-epi-Aspergillide A
European Journal of Organic Chemistry, 2012Co-Authors: Y. Sridhar, Pabbaraja SrihariAbstract:The stereoselective total syntheses of (+)-aspergillide B and (+)-7-epi-aspergillide A were achieved. The key reactions include Noyori's asymmetric transfer hydrogenation, an Achmatowicz Rearrangement, a Ferrier-type alkynylation, a hydrosilylation–protodesilylation, a CBS (Corey–Bakshi–Shibata) oxazaborolidine reduction, a Yamaguchi macrolactonization, and a Mitsunobu macrolactonization.
Weiping Tang - One of the best experts on this subject based on the ideXlab platform.
-
De Novo Synthesis of Mono- and Oligosaccharides via Dihydropyran Intermediates.
Chemistry an Asian journal, 2017Co-Authors: Wangze Song, Shuojin Wang, Weiping TangAbstract:The importance of carbohydrates is evident by their essential role in all living systems. Their syntheses have attracted attention from chemists for over a century. Most chemical syntheses in this area focus on the preparation of carbohydrates from naturally occurring monosaccharides. De novo chemical synthesis of carbohydrates from feedstock starting materials has emerged as a complementary method for the preparation of diverse mono- and oligosaccharides. In this review, the history of de novo carbohydrate synthesis is briefly discussed and particular attention is given to methods that address the formation of glycosidic bonds for potential de novo synthesis of oligosaccharides. Almost all methods of this kind involve the formation of dihydropyran intermediates. Recent progress in forming dihydropyrans by Achmatowicz Rearrangement, hetero-Diels-Alder cycloaddition, ring-closing metathesis, and other methods is also elaborated.
-
iridium catalyzed dynamic kinetic isomerization expedient synthesis of carbohydrates from Achmatowicz Rearrangement products
ChemInform, 2015Co-Authors: Haoyuan Wang, Ka Yang, Scott R Bennett, Shengrong Guo, Weiping TangAbstract:A highly stereoselective dynamic kinetic isomerization of Achmatowicz Rearrangement products is presented.
-
Chiral Catalyst-Directed Dynamic Kinetic Diastereoselective Acylation of Lactols for De Novo Synthesis of Carbohydrate
Organic letters, 2015Co-Authors: Haoyuan Wang, Ka Yang, Dan Yin, Can Liu, Daniel A. Glazier, Weiping TangAbstract:The control of the stereochemistry at the anomeric position is still one of the major challenges of synthetic carbohydrate chemistry. We have developed a new strategy consisting of a chiral catalyst-directed acylation followed by a palladium-catalyzed glycosidation to achieve high α- and β-stereoselectivity on the anomeric position. The former process involves a dynamic kinetic diastereoselective acylation of lactols derived from Achmatowicz Rearrangement, while the latter is a stereospecific palladium-catalyzed allylic alkylation.
-
Divergent de novo synthesis of all eight stereoisomers of 2,3,6-trideoxyhexopyranosides and their oligomers
Chemical communications (Cambridge England), 2015Co-Authors: Wangze Song, Yu Zhao, John C. Lynch, Hyunjin Kim, Weiping TangAbstract:All eight possible stereoisomers of 2,3,6-trideoxyhexopyranosides are prepared systematically from furan derivatives by a sequence of Achmatowicz Rearrangement, Pd-catalysed glycosidation, and chiral catalyst-controlled tandem reductions. This sequence provides access to all possible stereoisomers of naturally occurring rhodinopyranosides, amicetopyranosides, disaccharide narbosine B, and other unnatural oligomeric 2,3,6-trideoxyhexopyranosides. It comprises a unique and systematic strategy for the de novo synthesis of deoxysugars.
-
iridium catalyzed dynamic kinetic isomerization expedient synthesis of carbohydrates from Achmatowicz Rearrangement products
Angewandte Chemie, 2015Co-Authors: Haoyuan Wang, Ka Yang, Scott R Bennett, Shengrong Guo, Weiping TangAbstract:A highly stereoselective dynamic kinetic isomerization of Achmatowicz Rearrangement products was discovered. This new internal redox isomerization provided ready access to key intermediates for the enantio- and diastereoselective synthesis of a series of naturally occurring sugars. The nature of the de novo synthesis also enables the preparation of both enantiomers.
Jingyun Ren - One of the best experts on this subject based on the ideXlab platform.
-
Asymmetric total synthesis of (+)-attenol B.
Organic letters, 2015Co-Authors: Jingyun Ren, Jian Wang, Rongbiao TongAbstract:The more cytotoxic, thermodynamically less stable (+)-attenol B was isolated as a minor isomer of the spiroketal attenol A and synthesized previously as a minor product. Herein, we report a new strategy that for the first time led to asymmetric synthesis of (+)-attenol B as an exclusive product, featuring sequential Achmatowicz Rearrangement/bicycloketalization to efficiently construct the 6,8-dioxabicyclo[3.2.1]octane core. In addition, (−)-attenol A was obtained with 91% yield by isomerization of (+)-attenol B in CDCl3.
-
Asymmetric Total Synthesis of (+)-Didemniserinolipid B via Achmatowicz Rearrangement/Bicycloketalization
The Journal of organic chemistry, 2014Co-Authors: Jingyun Ren, Rongbiao TongAbstract:A new synthetic strategy was developed for the asymmetric total synthesis of (+)-didemniserinolipid B in 19 linear steps, featuring a highly efficient and enantioselective construction of 6,8-dioxabicyclo[3.2.1]octane (6,8-DOBCO) framework via a rarely explored Achmatowicz Rearrangement/bicycloketalization strategy. In addition, the first total synthesis of the proposed (+)-didemniserinolipid C was accomplished with 41.6% yield in 4 steps from a common advanced intermediate 18, and a possible revised structure of (+)-didemniserinolipid C was proposed. The new convergent synthetic strategy greatly expedites the entry to the didemniserinolipids and their analogues for biological activity evaluation.
-
asymmetric total synthesis of didemniserinolipid b via Achmatowicz Rearrangement bicycloketalization
Journal of Organic Chemistry, 2014Co-Authors: Jingyun Ren, Rongbiao TongAbstract:A new synthetic strategy was developed for the asymmetric total synthesis of (+)-didemniserinolipid B in 19 linear steps, featuring a highly efficient and enantioselective construction of 6,8-dioxabicyclo[3.2.1]octane (6,8-DOBCO) framework via a rarely explored Achmatowicz Rearrangement/bicycloketalization strategy. In addition, the first total synthesis of the proposed (+)-didemniserinolipid C was accomplished with 41.6% yield in 4 steps from a common advanced intermediate 18, and a possible revised structure of (+)-didemniserinolipid C was proposed. The new convergent synthetic strategy greatly expedites the entry to the didemniserinolipids and their analogues for biological activity evaluation.
-
Scalable Asymmetric Total Syntheses of (+)-Psoracorylifol B and (+)-ent-Psoracorylifol C
Organic letters, 2014Co-Authors: Jingyun Ren, Liyan Song, Yuan Liu, Rongbiao TongAbstract:The first, asymmetric total syntheses of potent antimicrobial Psoracorylifol B (>1.3 g obtained, dr 10.5:1) with a 9.4% overall yield on a gram scale in 14 steps and ent-Psoracorylifol C with a 4.3% yield in 16 steps were achieved. The key features of our synthesis include (i) sequential, rarely explored Achmatowicz Rearrangement/bicycloketalization to construct the 6,8-dioxabicyclo[3.2.1]octane core, and (ii) Cu-mediated SN2′ methylation or Johnson–Claisen Rearrangement to stereoselectively install the all-carbon quaternary stereocenter. This concise, highly efficient, and scalable synthetic route may provide expedited and practical access to psoracorylifols and their analogues for further biological activity evaluation.
-
Asymmetric Total Synthesis of (+)-Didemniserinolipid B via Achmatowicz Rearrangement/Bicycloketalization
2014Co-Authors: Jingyun Ren, Rongbiao TongAbstract:A new synthetic strategy was developed for the asymmetric total synthesis of (+)-didemniserinolipid B in 19 linear steps, featuring a highly efficient and enantioselective construction of 6,8-dioxabicyclo[3.2.1]octane (6,8-DOBCO) framework via a rarely explored Achmatowicz Rearrangement/bicycloketalization strategy. In addition, the first total synthesis of the proposed (+)-didemniserinolipid C was accomplished with 41.6% yield in 4 steps from a common advanced intermediate 18, and a possible revised structure of (+)-didemniserinolipid C was proposed. The new convergent synthetic strategy greatly expedites the entry to the didemniserinolipids and their analogues for biological activity evaluation