scholarly journals Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling

2020 ◽  
Vol 59 (34) ◽  
pp. 14647-14655
Author(s):  
Cheng‐Che Tsai ◽  
Christopher Sandford ◽  
Tao Wu ◽  
Buyun Chen ◽  
Matthew S. Sigman ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Statistical Modeling ◽  
Acid Catalysis ◽  
Allylic Substitution ◽  
Chiral Phosphoric Acid ◽  
Insight Into

Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling

2020 ◽  
Vol 132 (34) ◽  
pp. 14755-14763
Author(s):  
Cheng‐Che Tsai ◽  
Christopher Sandford ◽  
Tao Wu ◽  
Buyun Chen ◽  
Matthew S. Sigman ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Statistical Modeling ◽  
Acid Catalysis ◽  
Allylic Substitution ◽  
Chiral Phosphoric Acid ◽  
Insight Into

Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling

2020 ◽  
Author(s):  
Cheng-Che Tsai ◽  
Christopher Sandford ◽  
Tao Wu ◽  
Buyun Chen ◽  
Matthew S. Sigman ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Statistical Modeling ◽  
Noncovalent Interactions ◽  
Linear Regression Analysis ◽  
Nonlinear Effects ◽  
Allylic Substitution ◽  
Phosphate Anion ◽  
Carbon Centers ◽  
Chiral Phosphoric Acid ◽  
Multivariable Linear Regression Analysis

The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination of palladium and a chiral phosphoric acid was investigated by a combined experimental and statistical modeling approach. Experiments to probe nonlinear effects, the reactivity of deuterium-labeled substrates, and control experiments revealed that the chiral phosphate anion is involved in stereoinduction. Using multivariable linear regression analysis, we identified that the presence of multiple noncovalent interactions with the chiral environment of the phosphate anion are integral to enantiocontrol in the transition state. The synthetic protocol to form chiral pyrrolidines was further applied to the asymmetric construction of C−O bonds at fully-substituted carbon centers in the synthesis of chiral 2,2-disubstituted benzomorpholines.

Enantioselective Intramolecular Allylic Substitution via Synergistic Palladium/Chiral Phosphoric Acid Catalysis: Insight into Stereoinduction through Statistical Modeling

2020 ◽  
Author(s):  
Cheng-Che Tsai ◽  
Christopher Sandford ◽  
Tao Wu ◽  
Buyun Chen ◽  
Matthew S. Sigman ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Statistical Modeling ◽  
Noncovalent Interactions ◽  
Linear Regression Analysis ◽  
Nonlinear Effects ◽  
Allylic Substitution ◽  
Phosphate Anion ◽  
Carbon Centers ◽  
Chiral Phosphoric Acid ◽  
Multivariable Linear Regression Analysis

The mode of asymmetric induction in an enantioselective intramolecular allylic substitution reaction catalyzed by a combination of palladium and a chiral phosphoric acid was investigated by a combined experimental and statistical modeling approach. Experiments to probe nonlinear effects, the reactivity of deuterium-labeled substrates, and control experiments revealed that the chiral phosphate anion is involved in stereoinduction. Using multivariable linear regression analysis, we identified that the presence of multiple noncovalent interactions with the chiral environment of the phosphate anion are integral to enantiocontrol in the transition state. The synthetic protocol to form chiral pyrrolidines was further applied to the asymmetric construction of C−O bonds at fully-substituted carbon centers in the synthesis of chiral 2,2-disubstituted benzomorpholines.

Asymmetric C-H and N-H functionalization of Indoles involving Central Chirality via Chiral Phosphoric Acid Catalysis

2021 ◽  
Vol 18 ◽  
Author(s):  
Alemayehu Gashaw ◽  
Dereje Kebebew Debeli ◽  
Meseret Chemeda
Keyword(s):  
Phosphoric Acid ◽  
Organic Compounds ◽  
Organic Synthesis ◽  
Acid Catalysis ◽  
Bond Formation ◽  
Acid Catalysts ◽  
Asymmetric Syntheses ◽  
Chiral Phosphoric Acid ◽  
Great Progress ◽  
Interesting Area

: The C-H and N-H functionalization of indoles is an interesting area of research that has a useful impact on organic synthesis due to the availability of chiral indole scaffolds in the discovery of drugs, synthetic bioactive compounds, and natural products. The chiral phosphoric acid catalysts (CPAs) have proven to be a powerful and versatile class of enantioselective organocatalysts. Many asymmetric syntheses of organic compounds have been carried out with these catalysts in C–C and C-N bond formation reactions, and great progress has been reported. By 2011, several reviews were published covering some important topics and recent achievements in this field. Therefore, in this review, the most recent advances, research breakthroughs with key examples involving mechanisms of CPA-catalyzed C-H and N-H functionalization of indoles to form central chirality via Friedel Crafts, Michael type, and rearrangement reactions were reviewed and reported.

scholarly journals Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xingguang Li ◽  
Meng Duan ◽  
Peiyuan Yu ◽  
K. N. Houk ◽  
Jianwei Sun
Keyword(s):  
Hydrogen Bonding ◽  
Phosphoric Acid ◽  
Nucleophilic Addition ◽  
Acid Catalysis ◽  
Conjugate Addition ◽  
Mild Conditions ◽  
Rapid Construction ◽  
Chiral Phosphoric Acid ◽  
Cyclic Molecules ◽  
Selectivity Control

AbstractCatalytic asymmetric dearomatization (CADA) is a powerful tool for the rapid construction of diverse chiral cyclic molecules from cheap and easily available arenes. This work reports an organocatalytic enantioselective dearomatization of substituted thiophenes in the context of a rare remote asymmetric 1,10-conjugate addition. By suitable stabilization of the thiophenyl carbocation with an indole motif in the form of indole imine methide, excellent remote chemo-, regio-, and stereocontrol in the nucleophilic addition can be achieved with chiral phosphoric acid catalysis under mild conditions. This protocol can be successfully extended to the asymmetric dearomatization of other heteroarenes including selenophenes and furans. Control experiments and DFT calculations demonstrate a possible pathway in which hydrogen bonding plays an important role in selectivity control.

Asymmetric synthesis of CF3- and indole-containing tetrahydro-β-carbolines via chiral spirocyclic phosphoric acid-catalyzed aza-Friedel–Crafts reaction

2017 ◽  
Vol 4 (7) ◽  
pp. 1407-1410 ◽  
Author(s):  
En Xie ◽  
Abdul Rahman ◽  
Xufeng Lin
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Synthesis ◽  
Acid Catalysis ◽  
Chiral Phosphoric Acid ◽  
Acid Catalyzed ◽  
Quaternary Stereocenter

An enantioselective aza-Friedel–Crafts reaction of indoles with 1-trifluoromethyl-3,4-dihydro-β-carbolines has been developed to afford tetrahydro-β-carbolines with a CF3- and indole-containing quaternary stereocenter by using chiral phosphoric acid catalysis.

scholarly journals Chiral phosphoric acid-catalyzed stereodivergent synthesis of trisubstituted allenes and computational mechanistic studies

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiawen Wang ◽  
Sujuan Zheng ◽  
Subramani Rajkumar ◽  
Jinglei Xie ◽  
Na Yu ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Density Functional ◽  
Acid Catalysis ◽  
Chiral Molecules ◽  
Functional Theory ◽  
Chiral Phosphoric Acid ◽  
Acid Catalyzed ◽  
Asymmetric Additions ◽  
Formation Step ◽  
Stagger Form

Abstract Chiral molecules with multiple stereocenters are widely present in natural products and pharmaceuticals, whose absolute and relative configurations are both critically important for their physiological activities. In spite of the fact that a series of ingenious strategies have been developed for asymmetric diastereodivergent catalysis, most of these methods are limited to the divergent construction of point chirality. Here we report an enantioselective and diastereodivergent synthesis of trisubstituted allenes by asymmetric additions of oxazolones to activated 1,3-enynes enabled by chiral phosphoric acid (CPA) catalysis, where the divergence of the allenic axial stereogenicity is realized by modifications of CPA catalysts. Density functional theory (DFT) calculations are performed to elucidate the origin of diastereodivergence by the stacking- and stagger-form in the transition state (TS) of allene formation step, as well as to disclose a Münchnone-type activation mode of oxazolones under Brønsted acid catalysis.

The first catalytic asymmetric thioacetalization by chiral phosphoric acid catalysis

2016 ◽  
Vol 14 (7) ◽  
pp. 2205-2209 ◽  
Author(s):  
Jin-Sheng Yu ◽  
Wen-Biao Wu ◽  
Feng Zhou
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Mild Conditions ◽  
Chiral Phosphoric Acid ◽  
Catalytic Asymmetric

We report here the first catalytic asymmetric thioacetalization of salicylaldehyde and dithiol. Chiral phosphoric acid STRIP C5 is identified as a powerful catalyst for this reaction to afford various chiral dithioacetals in high to excellent yields and enantioselectivities under mild conditions.

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