ChemInform Abstract: Photoinduced Rearrangement Reaction of 2-(Pentamethyldisilanyloxymethyl)phenylpentamethyldisilane.

ChemInform ◽  
2010 ◽  
Vol 41 (32) ◽  
pp. no-no
Author(s):  
Seung Ki Park ◽  
Su Yeon Gong
Keyword(s):  
Rearrangement Reaction ◽  
Photoinduced Rearrangement

THE PHOTOINITIATED HALOGENATION REACTIONS OF N-BROMOACETANILIDE AND N-BROMO-2,4,6-TRICHLOROACETANILIDE

1966 ◽  
Vol 44 (13) ◽  
pp. 1555-1562
Author(s):  
Dennis D. Tanner ◽  
Eugene Protz
Keyword(s):  
Carbon Tetrachloride ◽  
Bromine Atom ◽  
Benzyl Bromide ◽  
Chain Process ◽  
Chain Mechanism ◽  
Chain Component ◽  
Rearrangement Reaction ◽  
A Chain ◽  
Photoinduced Rearrangement ◽  
Long Chain

The photoinduced rearrangement reaction of N-bromoacetanilide to p-bromoacetanilide in carbon tetrachloride was found to have a quantum efficiency approaching unity, and evidence is presented to indicate a chain component to the reaction process whose product-determining species is either the mesomeric acetanilide radical or the bromine atom. It was demonstrated that small variations in the solvent composition affected the product ratio of p- to o-bromoacetanilide. The reaction of N-bromoacetanilide in carbon tetrachloride with added toluene was found to be a long-chain process producing p-bromoacetanilide as well as acetanilide and benzyl bromide. The bromination of toluene by N-bromo-2,4,6-trichloroacetanilide was shown to proceed by a chain mechanism involving the bromine radical as the chain-propagating species, and this mechanism is used as a model to explain the reaction of N-bromoacetanilide in dilute carbon tetrachloride solutions of toluene.

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

2020 ◽  
Author(s):  
Nathan O'Brien ◽  
Naokazu Kano ◽  
Nizam Havare ◽  
Ryohei Uematsu ◽  
Romain Ramozzi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Bicyclic Compound ◽  
Compound A ◽  
Ligand System ◽  
Large Bulk ◽  
Rearrangement Reaction ◽  
Hydride Abstraction ◽  
Pentacoordinated Phosphorus ◽  
Acids And Bases

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

Photoinduced rearrangement of hydroxymethylisoxazolines, a route to enaminoaldehydes

1986 ◽  
Vol 51 (10) ◽  
pp. 2167-2180 ◽  
Author(s):  
Lubor Fišera ◽  
Nadezhda D. Kozhina ◽  
Peter Oravec ◽  
Hans-Joachim Timpe ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Thionyl Chloride ◽  
Quantum Yields ◽  
Acid Catalyzed ◽  
Catalyzed Reactions ◽  
Photoinduced Rearrangement ◽  
Condensed Heterocycles

3-Aryl-4-R-carbamoyl-5-hydroxymethylisoxazolines (IV) were synthesized by allowing R-NH2 amines with R = H, CH3, C3H7, C6H5C2H5, and NH2 to act on 3-(X-phenyl)-4-oxo-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles (III) with X = H, 4-CH3, 4-OCH3, 2-OCH3, 4-Cl, 2-Cl, 4-F, 2-F, 4-Br, 4-NO2, and 3-NO2. Exposed to radiation, the substances IV give Z-2-hydroxymethylamino-2-aryl-1-formylacrylamides (V) in good yields. The 4-Cl and 4-F substituted Z-derivatives V isomerize irreversibly to the E-derivatives VI if allowed to stand in solvent; the remaining derivatives V are stable. The quantum yields of the photoreaction are from 0.012 to 0.106 in dependence on the substituent X. In all cases where the compounds IV were used for the preparation of condensed heterocycles in conditions of acid-catalyzed reactions, lactones III were preferentially formed; the action of thionyl chloride on IV results in the formation of chloromethyl derivatives VIII, which do not undergo further cyclization.

scholarly journals Oxidative cyclo-rearrangement of helicenes into chiral nanographenes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chengshuo Shen ◽  
Guoli Zhang ◽  
Yongle Ding ◽  
Na Yang ◽  
Fuwei Gan ◽  
...  
Keyword(s):  
Functional Materials ◽  
Optical Devices ◽  
Oxidative Cyclization ◽  
Synthetic Chemistry ◽  
Aromatic Rings ◽  
Cyclization Reactions ◽  
Rearrangement Reaction ◽  
Skeletal Reconstruction ◽  
Gradual Release

AbstractNanographenes are emerging as a distinctive class of functional materials for electronic and optical devices. It is of remarkable significance to enrich the precise synthetic chemistry for these molecules. Herein, we develop a facile strategy to recompose helicenes into chiral nanographenes through a unique oxidative cyclo-rearrangement reaction. Helicenes with 7~9 ortho-fused aromatic rings are firstly oxidized and cyclized, and subsequently rearranged into nanographenes with an unsymmetrical helicoid shape through sequential 1,2-migrations. Such skeletal reconstruction is virtually driven by the gradual release of the strain of the highly distorted helicene skeleton. Importantly, the chirality of the helicene precursor can be integrally inherited by the resulting nanographene. Thus, a series of chiral nanographenes are prepared from a variety of carbohelicenes and heterohelicenes. Moreover, such cyclo-rearrangement reaction can be sequentially or simultaneously associated with conventional oxidative cyclization reactions to ulteriorly enrich the geometry diversity of nanographenes, aiming at innovative properties.

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).

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