ChemInform Abstract: Synthesis of α-Fluoro-β-hydroxy Esters by an Enantioselective Reformatsky-Type Reaction.

ChemInform ◽  
2012 ◽  
Vol 43 (30) ◽  
pp. no-no
Author(s):  
Michal Fornalczyk ◽  
Kuldip Singh ◽  
Alison M. Stuart
Keyword(s):  
Type Reaction ◽  
Hydroxy Esters

Investigating the Ritter Type Reaction of α-Methylene-β-hydroxy Esters in Acidic Medium: Evidence for the Intermediacy of an Allylic Cation

2013 ◽  
Vol 2013 (23) ◽  
pp. 5180-5187 ◽  
Author(s):  
Marcus M. Sá ◽  
Misael Ferreira ◽  
Giovanni F. Caramori ◽  
Laize Zaramello ◽  
Adailton J. Bortoluzzi ◽  
...  
Keyword(s):  
Acidic Medium ◽  
Type Reaction ◽  
Allylic Cation ◽  
Hydroxy Esters

Synthesis of α-fluoro-β-hydroxy esters by an enantioselective Reformatsky-type reaction

2012 ◽  
Vol 48 (29) ◽  
pp. 3500 ◽  
Author(s):  
Michal Fornalczyk ◽  
Kuldip Singh ◽  
Alison M. Stuart
Keyword(s):  
Type Reaction ◽  
Hydroxy Esters

Cerium-catalyzed reformatsky-type reaction with ethyl bromosuccinate for the synthesis of γ-lactones

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
S Muniz Machado Rodrigues ◽  
GVJ da Silva ◽  
M Gomes Constantino
Keyword(s):  
Type Reaction

Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

2020 ◽  
Vol 07 ◽  
Author(s):  
Christian Trapp ◽  
Corinna Schuster ◽  
Chris Drewniok ◽  
Dieter Greif ◽  
Martin Hofrichter
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Selective Reduction ◽  
Reducing Agents ◽  
Relative Configuration ◽  
Curtius Rearrangement ◽  
Keto Esters ◽  
Hydroxy Esters ◽  
Diastereoselective Reduction

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.

Intermolecular Rhodium-Catalyzed Carbometalation/Heck-Type Reaction in Water

2006 ◽  
Vol 118 (38) ◽  
pp. 6484-6486 ◽  
Author(s):  
Takuya Kurahashi ◽  
Hiroshi Shinokubo ◽  
Atsuhiro Osuka
Keyword(s):  
Type Reaction ◽  
Reaction In Water

Recent Developments in Heck-Type Reaction of Unactivated Alkenes and Alkyl Electrophiles

Synthesis ◽  
2020 ◽  
Author(s):  
Lili Shi ◽  
Junkai Fu ◽  
Shuangqiu Gao ◽  
Le Chang ◽  
Binglin Wang
Keyword(s):  
Heck Reaction ◽  
Alkyl Radicals ◽  
Type Reaction ◽  
The Past ◽  
Alkyl Electrophiles ◽  
Recent Developments ◽  
Palladium Catalyzed ◽  
Initial Work ◽  
Activated Olefins ◽  
Pseudo Halides

AbstractThe Mizoroki–Heck reaction is considered as one of the most ingenious and widely used methods for constructing C–C bonds. This reaction mainly focuses on activated olefins (styrenes, acrylates, or vinyl ethers) and aryl/vinyl (pseudo) halides. In comparison, the studies on unactivated alkenes and alkyl electrophiles are far less due to the low reactivity, poor selectivity, as well as competitive β-H elimination. In the past years, a growing interest has thus been devoted and significant breakthroughs have been achieved in the employment of unactivated alkenes and alkyl electrophiles as the reaction components, and this type of coupling is called as Heck-type or Heck-like reaction, which distinguishes from the traditional Heck reaction. Herein, we give a brief summary on Heck-type reaction between unactivated alkenes and alkyl electrophlies, covering its initial work, recent advancements, and mechanistic discussions.1 Introduction2 Intramolecular Heck-Type Reaction of Unactivated Alkenes and Alkyl Electrophiles2.1 Cobalt-Catalyzed Intramolecular Heck-Type Reaction2.2 Palladium-Catalyzed Intramolecular Heck-Type Reaction2.3 Nickel-Catalyzed Intramolecular Heck-Type Reaction2.4 Photocatalysis and Multimetallic Protocol for Intramolecular Heck-Type Reaction3 Intermolecular Heck-Type Reaction of Unactivated Alkenes and Alkyl Electrophiles3.1 Electrophilic Trifluoromethylating Reagent as Reaction Partners3.2 Alkyl Electrophiles as Reaction Partners4 Oxidative Heck-Type Reaction of Unactivated Alkenes and Alkyl Radicals5 Conclusions and Outlook

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