scholarly journals A concise access to bridged [2,2,1] bicyclic lactones with a quaternary stereocenter via stereospecific hydroformylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shuailong Li ◽  
Zhuangxing Li ◽  
Mingzheng Li ◽  
Lin He ◽  
Xumu Zhang ◽  
...  
Keyword(s):  
Enantiomeric Excess ◽  
Ester Group ◽  
Synthetic Methods ◽  
Hydroxyl Group ◽  
Structural Units ◽  
One Pot ◽  
Quaternary Stereocenter ◽  
High Yields ◽  
Bicyclic Lactones

AbstractChiral bridged [2,2,1] bicyclic lactones are privileged structural units in pharmaceutics and bioactive nature products. However, the synthetic methods for these compounds are rare. Here we report an efficient method for enantioselective construction of bridged [2,2,1] bicyclic lactones bearing a quaternary stereocenter via Rh-catalyzed asymmetric hydroformylation/intramolecular cyclization/pyridium chlorochromate (PCC) oxidation. By employing a hybrid phosphine-phosphite chiral ligand, a series of cyclopent-3-en-1-ols are transformed into corresponding γ-hydroxyl aldehydes with specific syn-selectivity. Then, hemiacetals form in situ and oxidation with PCC in one-pot affords bridged [2,2,1] bicyclic lactones in high yields and excellent enantiomeric excess. Replacing the hydroxyl group by an ester group, cyclopentanecarbaldehydes with a chiral all-carbon quaternary stereocenter in the γ-position can be generated efficiently.

scholarly journals Stereospecific Hydroformylation of 1-Substituted Cyclopent-3-en-1-ols: A Concise Access to Bridged [2, 2, 1] Bicyclic Lactones With A Quaternary Stereocenter

2021 ◽  
Author(s):  
Shuailong Li ◽  
Zhuangxing Li ◽  
Mingzheng Li ◽  
Lin He ◽  
Xumu Zhang ◽  
...  
Keyword(s):  
Efficient Method ◽  
Enantiomeric Excess ◽  
Ester Group ◽  
Hydroxyl Group ◽  
Chiral Ligand ◽  
One Pot ◽  
Quaternary Stereocenter ◽  
High Yields ◽  
Bicyclic Lactones

Abstract An efficient method for enantioselective construction of bridged [2, 2, 1] bicyclic lactones bearing a quaternary stereocenter was achieved by Rh-catalyzed asymmetric hydroformylation /intramolecular cyclization/PCC oxidation. By employing a hybrid phosphine-phosphite chiral ligand, a series of cyclopent-3-en-1-ols were transformed into their corresponding y-hydroxyl aldehydes with specific syn-selectivity, then hemiacetal formed in situ and oxidized by PCC in one-pot, affording bridged [2,2,1] bicyclic lactones in high yields and excellent enantiomeric excess. Replacing the hydroxyl group by an ester group, cyclopentanecarbaldehydes with a chiral all-carbon quaternary stereocenter in the γ-position can be generated efficiently. Gram-scale reaction and several transformations to corresponding amide, alcohol and acid demonstrated the practical value of this methodology.

scholarly journals Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes

2017 ◽  
Vol 13 ◽  
pp. 2023-2027 ◽  
Author(s):  
Hao Wang ◽  
Cui Chen ◽  
Weibing Liu ◽  
Zhibo Zhu
Keyword(s):  
Room Temperature ◽  
Synthetic Methods ◽  
Chemical Modifications ◽  
One Pot ◽  
Butyl Hydroperoxide ◽  
Radical Intermediates ◽  
Mild Conditions ◽  
Tert Butyl Hydroperoxide ◽  
Potential Applications

We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-(tert-butylperoxy)-2-iodoethanes, which are inaccessible through conventional synthetic methods. This method generates multiple radical intermediates in situ and has excellent regioselectivity, a broad substrate scope and mild conditions. The iodine and peroxide groups of 1-(tert-butylperoxy)-2-iodoethanes have several potential applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules.

Highly Selective One-Pot Synthesis of Polysubstituted Isoflavanes using Styryl Ethers and Electron-Withdrawing ortho-Quinone Methides Generated In Situ

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 189-192 ◽  
Author(s):  
Yujiro Hoshino ◽  
Kiyoshi Honda ◽  
Kenta Tanaka ◽  
Mami Kishimoto ◽  
Naoya Ohtsuka ◽  
...  
Keyword(s):  
Biologically Active ◽  
Quinone Methides ◽  
One Pot ◽  
One Pot Synthesis ◽  
Reaction Proceeds ◽  
Acidic Conditions ◽  
High Yields

A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho-quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.

Concise Synthesis of Tryptanthrin Spiro Analogues with In Vitro Antitumor Activity Based on One-Pot, Three-Component 1,3-Dipolar Cycloaddition of Azomethine Ylides to Сyclopropenes

Synthesis ◽  
2018 ◽  
Vol 51 (03) ◽  
pp. 713-729 ◽  
Author(s):  
Vitali Boitsov ◽  
Alexander Stepakov ◽  
Alexander Filatov ◽  
Nickolay Knyazev ◽  
Stanislav Shmakov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
One Pot ◽  
Economic Method ◽  
Reaction Proceeds ◽  
High Yields

A simple, efficient and atom-economic method has been developed for the synthesis of complex alkaloid-like compounds with spiro-fused indolo[2,1-b]quinazoline and cyclopropa[a]pyrrolizine or 3-azabicyclo[3.1.0]hexane moieties. We have found that one-pot, three-component 1,3-dipolar cycloaddition reactions allow the desired products to be obtained from various cyclopropene derivatives with tryptanthrin-derived azomethine ylides generated in situ, in good to high yields and excellent diastereoselectivity. The possibility of ylide generation was exemplified by using α-amino acids (l-proline, l-4-thiazolidincarboxylic acid) and simplest peptides (dipeptide Gly-Gly, tripeptide Gly-Gly-Gly). Quantum chemical investigations indicate that the reaction proceeds through the S-shaped azomethine ylide, the interaction of which with cyclopropenes proceeds via a less sterically hindered endo-transition state. The antitumor activity of some of spiro-tryptanthrin derivatives against erythroleukemia (K562), cervical carcinoma (HeLa) and colon carcinoma (CT26) cell lines was evaluated in vitro by MTS-assay.

scholarly journals One-Step Synthesis of Acylboron Compounds via Cu-Catalyzed Carbonylative Borylation of Alkyl Halides

2020 ◽  
Author(s):  
Cheng Li-Jie ◽  
Zhao Siling ◽  
Neal Mankad
Keyword(s):  
Alkyl Halides ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Acyl Halide ◽  
Reaction Conditions ◽  
One Pot ◽  
One Step ◽  
High Yields ◽  
Tertiary Alkyl

A Cu-catalyzed carbonylative borylation of unactivated alkyl halides has been developed, enabling efficient synthesis of aliphatic potassium acyltrifluoroborates (KATs) in high yields by treating the in-situ formed tetracoordinated acylboron intermediates with aqueous KHF2. A variety of functional groups are tolerated under the mild reaction conditions, and primary, secondary and tertiary alkyl halides are all applicable. In addition, this method also provides facile access to N-methyliminodiacetyl (MIDA) acylboronates as well as α-methylated potassium acyltrifluoroborates in a one-pot manner. Mechanistic studies indicate a radical atom transfer carbonylation (ATC) mechanism to form acyl halide intermediates that are subsequently borylated by (NHC)CuBpin.<br>

scholarly journals Asymmetric one-pot synthesis of cyclopropanes

2016 ◽  
Vol 35 (1) ◽  
pp. 45
Author(s):  
Naoufel Ben Hamadi ◽  
Ahlem Guesmi ◽  
Wided Nouira
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Protecting Group ◽  
Gram Positive ◽  
One Pot ◽  
Gram Negative ◽  
Activity Screening ◽  
High Yields

Cycloaddition of the diazoalkanes to electron-deficient olefins (in situ) affords polysubstituted cyclopropanes in high yields (up to 85%). Deprotection of the ketal protecting group provided water-soluble cyclopropane-bearing carbohydrate in good yields. Antimicrobial activity screening of the synthesized compounds 8 and 9, utilizing a variety of Gram-positive (Staphylococcus aureus and Enterococcus fecalis), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and yeast (Candida albicans), exhibited that all the prepared analogues acquire promising activities against both Gram-positive and Gram-negative bacteria especially compounds 9b and 9c (antimicrobial active agents against Gram-negative bacteria).

scholarly journals Highly Diastereoselective Synthesis of Tetrahydroquinoline Derivatives via [4 + 2] Annulation of Ortho-Tosylaminophenyl-Substituted Para-Quinone Methides and Cyanoalkenes

2021 ◽  
Vol 9 ◽  
Author(s):  
Taiwei Dong ◽  
Peifeng Wei ◽  
Min Li ◽  
Feng Gao ◽  
Yuan Qin
Keyword(s):  
Biologically Active ◽  
Structural Motif ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
Quinone Methides ◽  
One Pot ◽  
Reaction Performance ◽  
High Yields ◽  
Active Natural

As a privileged structural motif, tetrahydroquinoline skeletons widely exist in biologically active natural products and pharmaceuticals. In this protocol, a highly diastereoselective [4 + 2] annulation of ortho-tosylaminophenyl-substituted p-QMs and cyanoalkenes to construct tetrahydroquinoline derivatives has been successfully achieved. This strategy proceeds efficiently under mild condition, offering straightforward route to a variety of 4-aryl-substituted tetrahydroquinolines with high yields, excellent diastereoselectivities, broad functional group tolerance as well as gram-scale capacity. Moreover, a one-pot reaction sequence utilizing in situ generated p-QMs under the similar condition to build tetrahydroquinoline framework is smoothly conducted with good reaction performance as well as step and atom economy.

One-pot Nitration of Phenols under Mild and Heterogeneous Conditions

2001 ◽  
Vol 2001 (4) ◽  
pp. 140-142 ◽  
Author(s):  
Mohammad Ali Zolfigol ◽  
Mojtaba Bagherzadeh ◽  
Elahe Madrakian ◽  
Ezat Ghaemi ◽  
Abolfazl Taqian-Nasab
Keyword(s):  
Radical Cation ◽  
Nitrous Acid ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
One Pot ◽  
Oxidation Of Phenols ◽  
In Situ Generation ◽  
High Yields

Nitrophenols can be obtained via nitrosation–oxidation of phenols with Oxone®, NaNO2 and wet SiO2 at room temperature in moderate to high yields. In situ generation of HNO2 and the radical cation mechanism via the nitrous acid catalysed (NAC) pathway or hydrogen abstraction involving NO2 appear to be applicable to phenol nitration using these reagents.

Copper-Mediated One-Pot Synthesis of Indoles through Sequential Hydroamination and Cross-Dehydrogenative Coupling Reaction

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 75-84 ◽  
Author(s):  
Peng Sun ◽  
Jiaojiao Yang ◽  
Zirui Song ◽  
Yichao Cai ◽  
Yajie Liu ◽  
...  
Keyword(s):  
Mixed Solvents ◽  
Coupling Reaction ◽  
One Pot ◽  
One Pot Synthesis ◽  
Dehydrogenative Coupling ◽  
High Yields

Starting from simple anilines and ester arylpropiolates, an efficient one-pot synthesis of 2-arylindole-3-carboxylate derivatives has been developed through copper-mediated sequential hydroamination and cross-dehydrogenative coupling (CDC) reaction. The initial hydroamination of anilines to ester arylpropiolates in benzene can proceed in a stereoselective manner to give ester (Z)-3-(arylamino)acrylates in the presence of CuCl2/phenanthroline, KMnO4, and KHCO3 at 120 °C. Sequentially, these in situ functionalized adducts can undergo direct intramolecular oxidative alkenylation of aromatic C–H bond in mixed solvents (benzene/DMSO 1:1) at 130 °C affording multi-substituted­ indoles in good to high yields.

scholarly journals Endo-Selective Construction of Spiro-[butyrolactone-pyrrolidine] via Ag(I)/CAAA-Amidphos-Catalyzed 1,3-Dipolar Cycloaddition between Azomethine Ylides and α-Methylene-γ-Butyrolactone

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 28 ◽  
Author(s):  
Qinglin Hou ◽  
Yaoyao You ◽  
Xinluo Song ◽  
Yingxia Wang ◽  
Ke Chen ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Catalytic System ◽  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
Effective Strategy ◽  
Optimal Conditions ◽  
One Pot ◽  
Synthetic Organic Chemistry ◽  
Quaternary Stereocenter

Construction of spirocyclic pyrrolidines bearing a spiro quaternary stereocenter is an enormous challenge in synthetic organic chemistry. In this report, we introduce a Ag(I)/CAAA-amidphos-catalyzed enantioselective 1,3-dipolar cycloaddition between azomethine ylides and α-methylene-γ-butyrolactone as an effective strategy for the construction of excellent endo-selective spiro-[butyrolactone-pyrrolidine] derivatives. Meanwhile, the catalytic system was also successfully applied in the three-component one-pot reaction of azomethine ylides formed in situ under the action of N,N′-diisopropylcarbodiimide serving as a dehydrator. Under the optimal conditions, endo-pyrrolidine derivatives bearing a spiro quaternary stereocenter were obtained with high to excellent yields (up to 95% yield) and enantioselectivities (up to 93% ee).

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