ChemInform Abstract: An Advantageous Use of Palladium Compounds in Organic Synthesis. The Formation of Carbon-Carbon Bonds

ChemInform ◽  
1990 ◽  
Vol 21 (18) ◽  
Author(s):  
M. J. H. RUSSELL
Keyword(s):  
Organic Synthesis ◽  
Palladium Compounds ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds

scholarly journals Catalyst-controlled doubly enantioconvergent coupling of racemic alkyl nucleophiles and electrophiles

Science ◽  
2020 ◽  
Vol 367 (6477) ◽  
pp. 559-564 ◽  
Author(s):  
Haohua Huo ◽  
Bradley J. Gorsline ◽  
Gregory C. Fu
Keyword(s):  
Nickel Catalyst ◽  
Organic Synthesis ◽  
Side Reactions ◽  
Substitution Reactions ◽  
Stereochemical Control ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Single Stereoisomer

Stereochemical control in the construction of carbon-carbon bonds between an alkyl electrophile and an alkyl nucleophile is a persistent challenge in organic synthesis. Classical substitution reactions via SN1 and SN2 pathways are limited in their ability to generate carbon-carbon bonds (inadequate scope, due to side reactions such as rearrangements and eliminations) and to control stereochemistry when beginning with readily available racemic starting materials (racemic products). Here, we report a chiral nickel catalyst that couples racemic electrophiles (propargylic halides) with racemic nucleophiles (β-zincated amides) to form carbon-carbon bonds in doubly stereoconvergent processes, affording a single stereoisomer of the product from two stereochemical mixtures of reactants.

scholarly journals Some aspects of radical cascade and relay reactions

2017 ◽  
Vol 473 (2200) ◽  
pp. 20160859 ◽  
Author(s):  
Béatrice Quiclet-Sire ◽  
Samir Z. Zard
Keyword(s):  
Organic Synthesis ◽  
Structural Complexity ◽  
Metallic Nickel ◽  
Complex Structures ◽  
Important Benefit ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Strategic Impact ◽  
Radical Cascade ◽  
Radical Processes

The ability to create carbon–carbon bonds is at the heart of organic synthesis. Radical processes are particularly apt at creating such bonds, especially in cascade or relay sequences where more than one bond is formed, allowing for a rapid assembly of complex structures. In the present brief overview, examples taken from the authors' laboratory will serve to illustrate the strategic impact of radical-based approaches on synthetic planning. Transformations involving nitrogen-centred radicals, electron transfer from metallic nickel and the reversible degenerative exchange of xanthates will be presented and discussed. The last method has proved to be a particularly powerful tool for the intermolecular creation of carbon–carbon bonds by radical additions even to unactivated alkenes. Various functional groups can be brought into the same molecule in a convergent manner and made to react together in order to further increase the structural complexity. One important benefit of this chemistry is the so-called RAFT/MADIX technology for the manufacture of block copolymers of almost any desired architecture.

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