Metal-Free Synthesis of Trifluoromethyl Carbinol-Containing Imidazo[1,2-a]pyridines via Dehydrative Coupling of Imidazo[1,2-a]pyridines with Trifluoroacetaldehyde
Synthesis DOI: 10.1055/a-2254-0907 A facile and efficient method for the synthesis of trifluoromethylated carbinols has been developed from imidazo[1,2-a]pyridines and trifluoroacetaldehyde. The direct C(sp2)–H hydroxytrifluoromethylation is successfully implemented at room temperature using HFIP as solvent through dehydrative cross-coupling process, which displays a broad substrate scope and functional group tolerance. Furthermore, gram-scale and synthetic transformation experiments have also been demonstrated, which indicate its potential applicable values in organic synthesis. This green protocol features operational ...
Source: Synthesis - February 20, 2024 Category: Chemistry Authors: Liu, Zhaowen Guo, Xiaohua Chen, Zhixi Wu, Longhui Yang, Kai Tags: paper Source Type: research
Product Selectivity Control under Acidic and Basic Conditions on Oxidative Transformation of 1,3-Dicarbonyls Using Sodium Hypochlorite Pentahydrate
In this study, we reported that the reactivity of 1,3-dicarbonyls with sodium hypochlorite pentahydrate (NaOCl·5H2O) as an easy-to-handle oxidant, alters greatly depending on the pH value. The reaction of NaOCl·5H2O under weakly basic conditions (pH 12) gives the corresponding carboxylic acids in up to 97% yield. Upon addition of AcOH (pH 5), chlorination of active methylene sites proceeds efficiently to afford dichlorinated products in high yields. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synthesis)
Source: Synthesis - February 20, 2024 Category: Chemistry Authors: Kirihara, Masayuki Sakamoto, Yugo Tanaka, Takumi Kawai, Takuma Okada, Tomohide Kimura, Yoshikazu Takizawa, Shinobu Tags: paper Source Type: research
Divergent Reactivity of δ-Acetoxy Allenoates with 1,3-Bisnucleophiles: Synthesis of Multisubstituted Pyran, Dihydropyran, and 3-Vinylpent-2-enedioate Scaffolds
Synthesis DOI: 10.1055/s-0042-1751563 Base-dependent synthesis of tetrasubstituted pyrans or 3,4-dihydropyrans using δ-acetoxy allenoates and enolizable carbonyls like cyclohexan-1,3-dione and ethyl benzoylacetate is reported. Thus, the use of DMAP as an organocatalytic base gives tetrasubstituted pyrans while DBU affords isomeric tetrasubstituted 3,4-dihydropyrans. The reaction of δ-acetoxy allenoates with ethyl benzoylacetate mediated by KO
t
Bu furnishes diethyl 3-vinylpent-2-enedioates. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents...
Source: Synthesis - February 20, 2024 Category: Chemistry Authors: Khan, Shabbir Ahmed Swamy, K. C. Kumara Tags: paper Source Type: research
Unveiling Novel Synthetic Pathways through Brook Rearrangement
Conclusion [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synthesis)
Source: Synthesis - February 19, 2024 Category: Chemistry Authors: Agbaria, Mohamed Egbaria, Nwar Nairoukh, Zackaria Tags: short review Source Type: research
Access to 8-Aminoindolizine Fused with Quinone via Cu(OAc)2-Catalyzed Domino [4+2] Annulation
Synthesis DOI: 10.1055/a-2259-3283 Cu(OAc)2-catalyzed [4+2] annulation of N-substituted pyrrole-2-carbonitriles with quinones allowed access to a wide range of 8-aminoindolizines fused with quinones through a domino process involving a sequence of intermolecular Michael addition, Thorpe–Ziegler type cyclization, and aromatization. Biological evaluation of the resulting quinone-8-aminoindolizine hybrids revealed significant anticancer effects of these compounds in human hepatocellular cells (HepG2) and prostate adenocarcinoma cells (PC-3). [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in...
Source: Synthesis - February 19, 2024 Category: Chemistry Authors: Lee, Sunhee Lee, Yechan Namkung, Wan Kim, Ikyon Tags: paper Source Type: research
Exploring the Reactivity of Substituted [(Allyloxy)methyl]phosphonates in Cycloaddition and Coupling Reactions
Synthesis DOI: 10.1055/s-0042-1751554 This paper describes the versatility of substituted [(allyloxy)methyl]phosphonates to open the way to the synthesis of original phosphonated molecules with heterocyclic architectures. In 1,3-dipolar cycloaddition reactions with nitrile oxides, nitrile imines, and nitrones, these [(allyloxy)methyl]phosphonates react as dipolarophiles to give, regioselectively, the corresponding isoxazolines, pyrazolines, and isoxazolidines. Transition-metal-catalyzed reactions, including inter- or intramolecular Heck coupling, provided access to cinnamyl- and indenyl-linked moieties and phosphonated b...
Source: Synthesis - February 15, 2024 Category: Chemistry Authors: Jmai, Momtez Blot, Virginie Math é-Allainmat, Monique Efrit, Mohamed Lotfi Dubreuil, Didier M ’rabet, Hédi Lebreton, Jacques Tags: paper Source Type: research
Convenient Synthesis of Hexa- and Pentasaccharide Repeating Units Corresponding to the O-Polysaccharides of Acinetobacter baumannii O7 and Acinetobacter baumannii O10 Strains
Synthesis DOI: 10.1055/s-0042-1751559 The synthesis of the hexa- and pentasaccharide repeating units of the cell wall O-polysaccharides of Acinetobacter baumannii O7 and O10 strains, respectively, has been achieved in very good yield using [4+2] and [4+1] block glycosylation strategies. The p-methoxybenzyl (PMB) group was used as an in situ removable protecting group, which was removed after glycosylation in the same pot by tuning the reaction condition. A challenging β-l-rhamnopyranosyl linkage was constructed using ‘armed-disarmed glycosylation’ conditions by the influence of a remotely located, H-bond mediating, pi...
Source: Synthesis - February 14, 2024 Category: Chemistry Authors: Sahaji, Samim Bag, Puja Misra, Anup Kumar Tags: paper Source Type: research
Nicholas Reactions of Pentadiynyl –Co2(CO)6 Cations. Synthesis of Antimalarial Hinokiresinol Analogues
Synthesis DOI: 10.1055/a-2250-8050 Penta-1,4-diyn-3-ol–Co2(CO)6 complexes undergo Lewis acid mediated Nicholas reactions with high selectivity at the C-3 site, to give skipped (1,4-)diyne complexes. The compatible nucleophiles have a wide range of reactivity. The methodology has been applied to the synthesis of both (E)- and (Z)-isomers of a hinokiresinol and nyasol analogue, the (E)-isomer of which is known to have elevated antiplasmodial and antimalarial activity. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full text (Source: Synthesis)
Source: Synthesis - February 14, 2024 Category: Chemistry Authors: Muresan, Marcus Green, James R. Tags: paper Source Type: research
I2-Catalyzed Oxidative Acylation of Tertiary Amines via C –N Bond Cleavage
Synthesis DOI: 10.1055/a-2256-9837 The development of catalysts for the amidation of tertiary amines with acyl chlorides through oxidative C–N bond cleavage is rather challenging. By employing iodine as the catalyst, a broad range of aromatic acyl chlorides and tertiary amines are efficiently converted into amides in good yields under mild conditions. A plausible mechanistic pathway is proposed for this transformation and is supported by appropriate control experiments. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full tex...
Source: Synthesis - February 14, 2024 Category: Chemistry Authors: Ge, Xin Lei, Ping Su, Qin Pan, Ying-Ming Ablajan, Keyume Tags: paper Source Type: research
Zinc/Bismuth-Mediated Allylation Reaction of Biomass Feedstocks: Synthesis of Furanic Diols
Synthesis DOI: 10.1055/a-2241-6966 Biomass-based diols have been synthesized by a Zn/Bi-mediated Barbier-type of reaction from furanic aldehydes and allyl halides to access allylated diols. The allylated diols can be readily converted into alkylated diols by hydrogenation. These furanic diols could be potential replacements for fossil fuel based bisphenol A (BPA) which has an adverse endocrine-disrupting effect on humans. This mild and green protocol provides symmetric and nonsymmetric diols in high yields. A chemoselective reduction of allylic double bonds provides diols with unique substitution. [...] Georg Thieme Verlag...
Source: Synthesis - February 14, 2024 Category: Chemistry Authors: Biswas, Soumen Kannaboina, Prakash Sibi, Mukund P. Tags: paper Source Type: research
Stereoselective Synthesis of 3,4-Dihydrobenzofuro[3,2-b]pyridin-2(1H)-ones Enabled by Pd/Chiral Isothiourea Relay Catalysis
Synthesis DOI: 10.1055/s-0043-1763679 A highly enantioselective [4+2] cyclization of azadienes with ketene in situ generated from Pd-catalyzed carbonylation of benzyl bromides, is established through Pd/chiral isothiourea relay catalysis. The key in this transformation is the formation of a C1-ammonium enolate from the in situ generated ketene and a chiral isothiourea catalyst, which subsequently undergoes a formal [4+2] reaction, leading to 3,4-dihydrobenzofuro[3,2-b]pyridine derivatives in high yields and excellent levels of stereoselectivity. [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArtic...
Source: Synthesis - February 13, 2024 Category: Chemistry Authors: Sayed, Mostafa Shi, Zhipeng Fan, Tao Shen, Hong-Cheng Han, Zhi-Yong Tags: paper Source Type: research
K2CO3-Mediated Intramolecular Oxa-Michael Cyclization of α,β-Unsaturated Ketoximes: Synthesis of Densely Arene-Substituted 2-Isoxazolines Bearing a Quaternary Center
Synthesis DOI: 10.1055/a-2242-6435 An efficient K2CO3-mediated intramolecular oxa-Michael cyclization of β,β-diarylated α,β-unsaturated ketoximes is described. This methodology allows access to arene-rich 2-isoxazoline derivatives bearing a quaternary center in excellent yields with an operationally simple experimental procedure. Deuterium-scrambling experiments were carried out to shed light on the reaction pathway. To demonstrate the synthetic utility of the method, a large-scale synthesis and Ullmann-type C–N bond-formation reaction between pyrazole and dibrominated isoxazoline was performed. [...] Georg Thieme Ve...
Source: Synthesis - February 13, 2024 Category: Chemistry Authors: Jat, Ram Singh Kothapalli, Raveendrababu Bhanuchandra, M. Tags: paper Source Type: research
Efficient Synthesis of (2Z,5Z)-3-Benzyl/alkyl-5-(2-oxo-5-aryl-3 (2H)-furanylidene)-2-(phenylimino)-1,3-thiazolidin-4-ones via a One-Pot Three-Component Reaction
Synthesis DOI: 10.1055/s-0042-1751557 A simple and efficient strategy for the chemoselective synthesis of (2Z,5Z)-3-benzyl/alkyl-5-(2-oxo-5-arylfuran-3(2H)-ylidene)-2-(phenylimino)thiazolidin-4-one derivatives is developed via a sequential three-component reaction of readily available phenacyl bromides, pyridine and methyl 2-(3-benzyl/alkyl-4-oxo-2-(phenylimino)thiazolidin-5-ylidene)acetates in acetonitrile at room temperature. The advantages of this one-pot sequential Michael addition/1,2-H shift/elimination of pyridine/intramolecular cyclization are highlighted by its low energy requirements (short reaction times at room...
Source: Synthesis - February 13, 2024 Category: Chemistry Authors: Alizadeh, Abdolali Moterassed, Reihaneh Tags: paper Source Type: research
Total Synthesis of Daphniphyllum Alkaloids: (+)-Daphlongamine E, (+)-Calyciphylline R, and ( –)-10-Deoxydaphnipaxianine A
Synthesis DOI: 10.1055/a-2244-1600 Here, we wish to describe our detailed efforts in the total synthesis of three calyciphylline A-type alkaloids, namely (+)-daphlongamine E, (+)-calyciphylline R, and (–)-10-deoxydaphnipaxianine A. Important steps in our approach include a Pt-catalyzed nitrile hydration, a Babler–Dauben rearrangement, a novel selective amide reduction tactic, and an oxidative Nazarov cyclization via an unfunctionalized tertiary divinyl carbinol (TDC). [...] Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents | Abstract | Full tex...
Source: Synthesis - February 13, 2024 Category: Chemistry Authors: Zhang, Yan Chen, Yuye Xu, Jing Tags: feature Source Type: research
Synform issue 2024/3
Synthesis 2024; 56: A36-A52 DOI: 10.1055/s-0040-1720624 Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals: Table of contents (Source: Synthesis)
Source: Synthesis - February 13, 2024 Category: Chemistry Authors: Zanda, Matteo Tags: Synform Source Type: research
