Scholl reaction
The Scholl reaction is a name reaction from the field of organic chemistry and was first observed in 1910 by Roland Scholl (1865–1945). A coupling of aromatics takes place here.
Overview reaction
The Scholl reaction is carried out in the presence of catalytic amounts of a Lewis acid .
A direct bond is created between the two aromatic rings (shown in green in the formula scheme). During the reaction, a formal place elimination of hydrogen instead that by the addition of sodium chloride or hydrogen chloride is favored. The reaction can be carried out and continued with any aromatic compound.
Possible mechanism
The following mechanism of the Scholl reaction is explained using benzene and aluminum chloride (AlCl 3 ).
As a Lewis base, the benzene ( 1 ) attacks the Lewis acid aluminum chloride and the dearomatized, ionic intermediate 2 is formed , which is attacked by another benzene as a Lewis base. The newly formed intermediate now undergoes two hydride shifts to intermediate 4 . By splitting off the aluminum chloride, the stable 1,2-dihydro-1,1'-biphenyl ( 5 ) is now formed . The rearomatized end product biphenyl ( 6 ) is produced by air oxidation or another oxidizing agent .
application
The Scholl reaction is used in the production of polycyclic aromatics and nanotubes .
literature
- Bradford P. Mundy, Michael G. Ellerd, Frang G. Favaloro Jr .: Name Reactions and Reagents in Organic Synthesis. 2nd Edition. John Wiley & Sons, New York 2005, ISBN 0-471-22854-0 , p. 578.
- Zerong Wang: Comprehensive Organic Name Reactions and Reagents. 1st edition. John Wiley & Sons, Ney Jersey 2009, ISBN 978-0-471-70450-8 , pp. 2518-2521.
- Martha Windholz: The Merck Index. 9th edition. Merck & Co., New Jersey 1976, ISBN 0-911910-26-3 , p. 81.