Aryne-mediated [2,3]-sigmatropic rearrangement of tertiary 2,3-allenylamines bearing an electron-withdrawing group at the α-position

2021 ◽  
Author(s):  
Lu Han ◽  
Xue-Ting Zhang ◽  
Dong Xie ◽  
Shi-Kai Tian
Keyword(s):  
Sigmatropic Rearrangement ◽  
Rearrangement Reaction ◽  
Electron Withdrawing Group

An unprecedented [2,3]-sigmatropic rearrangement reaction of quaternary 2,3-allenylammonium ylides, generated in situ from tertiary 2,3-allenylamines and arynes, has been established. With 2-(trimethylsilyl)aryl triflates as aryne precursors, a range of tertiary...

Catalyst-Free [2,3]-Sigmatropic Rearrangement Reactions of Photochemically Generated Ammonium Ylides

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4348-4358 ◽  
Author(s):  
Fang Li ◽  
Feifei He ◽  
Rene M. Koenigs
Keyword(s):  
Visible Light ◽  
Sigmatropic Rearrangement ◽  
Tertiary Amines ◽  
Amino Esters ◽  
Catalyst Free ◽  
Rearrangement Reaction ◽  
Rearrangement Reactions ◽  
Free Ammonium

The rearrangement reaction of ammonium ylides furnishes valuable α,α-disubstituted amino esters. In this work, we describe the visible-light photolysis reaction of aryldiazoacetates in the presence of tertiary amines that react via a free ammonium ylide in a sigmatropic rearrangement reaction to provide amino esters in moderate to very good yields (33 examples, up to 97% yield).

scholarly journals Theoretical Study of Sigmatropic Rearrangement of Cycloprop-2-en-1-ol and its Fluorine Derivatives: Pericyclic or Pseudopericyclic Character from NICS and LLPE

2019 ◽  
Vol 31 (3) ◽  
pp. 597-601
Author(s):  
A. Sangeetha ◽  
A. Thaminum Ansari ◽  
Jebakumar Jeevanandam ◽  
S. Jayaprakash
Keyword(s):  
Oxygen Atom ◽  
Gas Phase ◽  
Energy Barrier ◽  
Fluorine Atom ◽  
Theoretical Study ◽  
Lone Pair ◽  
Sigmatropic Rearrangement ◽  
Nucleus Independent Chemical Shift ◽  
Lone Pair Electron ◽  
Rearrangement Reaction

Sigmatropic rearrangement reaction of cycloprop-2-en-1-ol and its fluorine derivatives has been studied theoretically in gas phase and its energy barrier has been calculated. Nucleus-independent chemical shift (NICS) shows sigmatropic rearrangement of cycloprop-2-en-1-ol is pericyclic in nature whereas fluorine derivatives show pseudopericyclic and pericyclic nature. Substitution of fluorine atom at ring is found to increase the energy barrier for –OH migration, while substitution at oxygen atom reduces the barrier. To know the involvement of lone pair of electrons during the reaction, lone pair electron present on oxygen atom is locked by hydrogen bonding. CR-CCSD(T)/6-311+G** levels are used to study the reactions more accurately.

scholarly journals Vanadium-catalyzed selenide oxidation with in situ [2,3] sigmatropic rearrangement (SOS reaction): scope and asymmetric applications

2004 ◽  
Vol 2 (9) ◽  
pp. 1315-1329 ◽  
Author(s):  
T. Campbell Bourland ◽  
Rich G. Carter ◽  
Alexandre F. T. Yokochi
Keyword(s):  
Sigmatropic Rearrangement

scholarly journals Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3+ + 2]-cycloaddition/rearrangement reactions

2018 ◽  
Vol 14 ◽  
pp. 1826-1833 ◽  
Author(s):  
Lin-bo Luan ◽  
Zi-jie Song ◽  
Zhi-ming Li ◽  
Quan-rui Wang
Keyword(s):  
Cycloaddition Reaction ◽  
Ring Expansion ◽  
Aluminium Chloride ◽  
Phenyl Substituent ◽  
Rearrangement Reaction ◽  
Rearrangement Reactions

Two new series of tricyclic heterocycles, namely 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral, free bases 13 were synthesized from 4-acetoxy-1-acetyl-4-phenylazo-1,2,3,4-tetrahydroquinolines 8 and nitriles 9 in the presence of aluminium chloride by the [3+ + 2]-cycloaddition reaction of the in situ generated azocarbenium intermediates 14 followed by a ring-expansion rearrangement. In the rearrangement reaction, the phenyl substituent in the initially formed spiro-triazolium adducts 16 underwent a [1,2]-migration from C(3) to the electron-deficient N(2). This led to the ring expansion from 6-membered piperidine to 7-membered diazepine furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines.

Acylation of Nitronates: [3,3]-Sigmatropic Rearrangement of in Situ Generated N-Acyloxy,N-oxyenamines

2018 ◽  
Vol 83 (18) ◽  
pp. 11057-11066 ◽  
Author(s):  
Aleksandr O. Kokuev ◽  
Yulia A. Antonova ◽  
Valentin S. Dorokhov ◽  
Ivan S. Golovanov ◽  
Yulia V. Nelyubina ◽  
...  
Keyword(s):  
Sigmatropic Rearrangement
Sign in / Sign up

Export Citation Format

Share Document