Ring Expansion of 2‐(α‐Hydroxyalkyl)azetidines: A Synthetic Route to Functionalized Pyrrolidines

2008 ◽  
Vol 2008 (19) ◽  
pp. 3286-3297 ◽  
Author(s):  
François Durrat ◽  
Monica Vargas Sanchez ◽  
François Couty ◽  
Gwilherm Evano ◽  
Jérôme Marrot
Keyword(s):  
Ring Expansion ◽  
Synthetic Route

Oxidative Dearomatization and Sigmatropic 1,3-Acyl Shift in Excited State: Aromatics to Embellished cis-Hydrindanes

Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1633-1642
Author(s):  
Vishwakarma Singh ◽  
Raghaba Sahu
Keyword(s):  
Excited State ◽  
Ring Expansion ◽  
Synthetic Route ◽  
Oxidative Dearomatization ◽  
Key Features

A stereoselective synthetic route to embellished cis-hydrindanes from simple aromatic precursors is described. Oxidative dearomatization, ring expansion, and photochemical 1,3-acyl shift are the key features of our approach. Oxidative dearomatization of o-(hydroxymethyl)phenols followed by π4s + π2s cycloaddition furnishes bicyclo[2.2.2]octanes with contiguous keto epoxide groups, which upon ring expansion lead to bicyclo[3.2.2]nonanes endowed with a β,γ-enone chromophore. Unbridging of bicyclo[3.2.2]nonanes upon singlet excitation furnishes embellished cis-hydrindanes.

scholarly journals New Syntheses and Ring Expansion Reactions of Cyclobutenimines

2010 ◽  
Vol 63 (12) ◽  
pp. 1656 ◽  
Author(s):  
Ernst Schaumann ◽  
Gerrit Oppermann ◽  
Michael Stranberg ◽  
Harold W. Moore
Keyword(s):  
Carbonyl Group ◽  
Ring Expansion ◽  
Synthetic Route ◽  
Tertiary Alcohols ◽  
Ring Enlargement ◽  
Alkyl Derivatives

Two routes are reported for the synthesis of iminocyclobutenones having N-(het)aryl substitution: an addition/substitution sequence starting with cyclobutenediones and an aza-Wittig method. A new synthetic route to N-alkyl derivatives is also presented. This involves O-alkylation of 3-alkylamino-1,2-cyclobutenediones using Meerwein’s reagent and subsequent deprotonation under non-hydrolytic conditions. Lithium organyls were found to add to the remaining carbonyl group. The resulting tertiary alcohols undergo ring enlargement on heating in xylene to give 4-aminophenols, 4-amino-1-naphthols, or cyclopenta-annulated quinolines from 4-vinyl, 4-aryl, and 4-alkynyl derivatives, respectively.

ChemInform Abstract: Ring Expansion of 2-(α-Hydroxyalkyl)azetidines: A Synthetic Route to Functionalized Pyrrolidines.

ChemInform ◽  
2008 ◽  
Vol 39 (44) ◽  
Author(s):  
Francois Durrat ◽  
Monica Vargas Sanchez ◽  
Francois Couty ◽  
Gwilherm Evano ◽  
Jerome Marrot
Keyword(s):  
Ring Expansion ◽  
Synthetic Route

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>

A General Convergent Strategy for the Synthesis of Tetrasubstituted Furan Fatty Acids (FuFAs)

2019 ◽  
Author(s):  
Yamin Wang ◽  
Gareth Pritchard ◽  
Marc Kimber
Keyword(s):  
Fatty Acids ◽  
Spectral Data ◽  
Synthetic Route ◽  
Furan Fatty Acids

Synthetic route for the synthesis of tetrasubstituted furan fatty acids; including experimental details, characterisation, and spectral data of all intermediates.

Palladium-Catalyzed Asymmetric Annulation Between Aryl Iodides and Racemic Epoxides Using a Chiral Norbornene Cocatalyst

2018 ◽  
Author(s):  
Guangbin Dong ◽  
Renhe Li
Keyword(s):  
Isopropyl Ester ◽  
Synthetic Route ◽  
Initial Development ◽  
Aryl Iodides ◽  
Palladium Catalyzed

Herein, we describe our initial development of an asymmetric Pd-catalyzed annulation between aryl iodides and racemic epoxides for synthesis of 2,3-dihydrobenzofurans using a chiral norbornene cocatalyst. A series of enantiopure ester-, amide- and imide-substituted norbornenes have been prepared with a reliable synthetic route. Promising enantioselectivity (42-45% ee) has been observed using the isopropyl ester-substituted norbornene (N1*) and the amide-substituted norbornene (N7*).

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