An enantioconvergent halogenophilic nucleophilic substitution (SN2X) reaction

Science ◽  
2019 ◽  
Vol 363 (6425) ◽  
pp. 400-404 ◽  
Author(s):  
Xin Zhang ◽  
Jingyun Ren ◽  
Siu Min Tan ◽  
Davin Tan ◽  
Richmond Lee ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Nucleophilic Substitution ◽  
Steric Hindrance ◽  
Substitution Reaction ◽  
Common Variant ◽  
Nucleophilic Attack ◽  
Mechanistic Studies ◽  
Leaving Group

Bimolecular nucleophilic substitution (SN2) plays a central role in organic chemistry. In the conventionally accepted mechanism, the nucleophile displaces a carbon-bound leaving group X, often a halogen, by attacking the carbon face opposite the C–X bond. A less common variant, the halogenophilic SN2X reaction, involves initial nucleophilic attack of the X group from the front and as such is less sensitive to backside steric hindrance. Herein, we report an enantioconvergent substitution reaction of activated tertiary bromides by thiocarboxylates or azides that, on the basis of experimental and computational mechanistic studies, appears to proceed via the unusual SN2X pathway. The proposed electrophilic intermediates, benzoylsulfenyl bromide and bromine azide, were independently synthesized and shown to be effective.

scholarly journals NUCLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN

2010 ◽  
Vol 5 (3) ◽  
pp. 203-206
Author(s):  
Bambang Purwono ◽  
Estiana R. P. Daruningsih
Keyword(s):  
Nucleophilic Substitution ◽  
Mannich Reaction ◽  
Substitution Reaction ◽  
Mannich Base ◽  
Nucleophilic Substitution Reaction ◽  
Substitution Reactions ◽  
Halide Salt ◽  
Leaving Group ◽  
Dimethyl Amine ◽  
Halide Salts

The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded 93.28 %. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyano)methylbenzaldehyde in 54.39% yield. Reaction with methoxyde ion yielded 4-hydroxy- 3-methoxy-5-(methoxy) -methylbenzaldehyde in 67.80% yield. The nucleophilic substitution reaction showed that trimethylamino substituent of quaternary Mannich base can act as a good leaving group on nucleophilic substitution reactions. Keywords: Mannich reaction, vanillin, nucleophilic substitution

Radical mechanism of a nucleophilic reaction depending on a two-dimensional structure

2018 ◽  
Vol 20 (1) ◽  
pp. 489-497 ◽  
Author(s):  
Wenchuan Lai ◽  
Yuehui Yuan ◽  
Xu Wang ◽  
Yang Liu ◽  
Yulong Li ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction ◽  
Dimensional Structure ◽  
Radical Mechanism ◽  
Two Dimensional ◽  
Nucleophilic Reaction ◽  
Two Dimensional Materials ◽  
Fluorinated Graphene

This study reveals the radical mechanism of the nucleophilic substitution reaction of fluorinated graphene depending on its two-dimensional structure, which can be used to represent the chemistry characteristics of two-dimensional materials while enriching the research on nucleophilic substitution in the field of organic chemistry.

Stereoselective Synthesis of Multisubstituted α-fluoro-β-lactams

2020 ◽  
Vol 24 (18) ◽  
pp. 2169-2180
Author(s):  
Atsushi Tarui ◽  
Yukiko Karuo ◽  
Kazuyuki Sato ◽  
Kentaro Kawai ◽  
Masaaki Omote
Keyword(s):  
Nucleophilic Substitution ◽  
Substitution Reaction ◽  
Stereoselective Synthesis ◽  
Nucleophilic Substitution Reaction ◽  
Nucleophilic Attack ◽  
Type Reaction ◽  
Lactam Ring ◽  
Metal Catalyzed ◽  
Cyclic Compounds ◽  
Nucleophilic Acyl Substitution

β-Lactams, found in β -lactam antibiotics, are the structurally distorted cyclic compounds being subjected to nucleophilic acyl substitution reaction. α-Fluorination of β -lactams is a simple and expedient approach to control the reactivity of β-lactam ring toward nucleophilic attack, which would hopefully lead to the new design of future antibiotics. From the viewpoint of obtaining multisubstituted α -fluoro-β-lactams, α -bromo-α- fluoro-β-lactams are considered as key compounds for structure functionalization, including nucleophilic substitution reaction, aldol-type reaction and metal-catalyzed crosscoupling reaction. All the reactions can be conducted smoothly to afford a variety of multisubstituted α-fluoro-β-lactams. During the course of the examination, chiral α,α-difluoro- β-lactams and α -bromo-β-fluoro-α-lactams are successfully obtained, which are considered potent precursors for making stereocontrolled multisubstituted α-fluoro-β-lactams.

scholarly journals Synthesis of Carbohydrate Based Macrolactones and Their Applications as Receptors for Ion Recognition and Catalysis

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3394
Author(s):  
Surya B. Adhikari ◽  
Anji Chen ◽  
Guijun Wang
Keyword(s):  
Nucleophilic Substitution ◽  
Supramolecular Chemistry ◽  
Copper Sulfate ◽  
Substitution Reaction ◽  
Biological Properties ◽  
Anion Binding ◽  
Nucleophilic Substitution Reaction ◽  
Binding Properties ◽  
Intramolecular Nucleophilic Substitution ◽  
Leaving Groups

Glycomacrolactones exhibit many interesting biological properties, and they are also important in molecular recognitions and for supramolecular chemistry. Therefore, it is important to be able to access glycomacrocycles with different sizes and functionality. A new series of carbohydrate-based macrocycles containing triazole and lactone moieties have been designed and synthesized. The synthesis features an intramolecular nucleophilic substitution reaction for the macrocyclization step. In this article, the effect of some common sulfonate leaving groups is evaluated for macrolactonization. Using tosylate gave good selectivity for monolactonization products with good yields. Fourteen different macrocycles have been synthesized and characterized, of which eleven macrocycles are from cyclization of the C1 to C6 positions of N-acetyl D-glucosamine derivatives and three others from C2 to C6 cyclization of functionalized D-glucosamine derivatives. These novel macrolactones have unique structures and demonstrate interesting anion binding properties, especially for chloride. The macrocycles containing two triazoles form complexes with copper sulfate, and they are effective ligands for copper sulfate mediated azide-alkyne cycloaddition reactions (CuAAC). In addition, several macrocycles show some selectivity for different alkynes.

Lewis-Acid-Catalyzed Direct Nucleophilic Substitution Reaction of Alcohols for the Functionalization of Aromatic Amines

2019 ◽  
Vol 4 (4) ◽  
pp. 1371-1374 ◽  
Author(s):  
Onkar S. Nayal ◽  
Maheshwar S. Thakur ◽  
Rohit Rana ◽  
Rahul Upadhyay ◽  
Sushil K. Maurya
Keyword(s):  
Nucleophilic Substitution ◽  
Lewis Acid ◽  
Aromatic Amines ◽  
Substitution Reaction ◽  
Nucleophilic Substitution Reaction ◽  
Acid Catalyzed

scholarly journals Transition-Metal-Free Boryl Substitution Using Silylboranes and Alkoxy Bases

Synlett ◽  
2017 ◽  
Vol 28 (11) ◽  
pp. 1258-1267 ◽  
Author(s):  
Hajime Ito ◽  
Eiji Yamamoto ◽  
Satoshi Maeda ◽  
Tetsuya Taketsugu
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
Experimental Studies ◽  
Transition Metal Catalysts ◽  
Alkyl Halides ◽  
Aryl Halides ◽  
Nucleophilic Attack ◽  
Important Class ◽  
Mechanistic Studies ◽  
Induced Reaction

Silylboranes are used as borylation reagents for organohalides in the presence of alkoxy bases without transition-metal catalysts. PhMe2Si–B(pin) reacts with a variety of aryl, alkenyl, and alkyl halides, including sterically hindered examples, to provide the corresponding organoboronates in good yields with high borylation/silylation ratios, showing good functional group compatibility. Halogenophilic attack of a silyl nucleophile on organohalides, and subsequent nucleophilic attack on the boron electrophile are identified to be crucial, based on the results of extensive theoretical and experimental studies. This boryl­ation reaction is further applied to the first direct dimesitylboryl (BMes2) substitution of aryl halides using Ph2MeSi–BMes2 and Na(O-t-Bu), affording aryldimesitylboranes, which are regarded as an important class of compounds for organic materials.1 Introduction2 Boryl Substitution of Organohalides with PhMe2Si–B(pin)/Alkoxy Bases3 Mechanistic Investigations4 DFT Mechanistic Studies Using an Artificial Force Induced Reaction (AFIR) Method5 Dimesitylboryl Substitution of Aryl Halides with Ph2MeSi–BMes2/Na(O-t-Bu)6 Conclusion

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