PREPARATION OF a,b-UNSATURATED ALDEHYDES via THE WITTIG REACTION: CYCLOHEXYLIDENEACETALDEHYDE

1973 ◽  
Vol 53 ◽  
pp. 104 ◽  
2021 ◽  
Author(s):  
Elena Fernandez ◽  
Oriol Salvado

We describe the preparation of densely functionalised 1,1,-silylborylated trisubstituted alkenes, via boron-Wittig reaction, between LiC(Bpin)2(SiMe3) and aliphatic or aromatic aldehydes. The condensation of diborylsilylmethide lithium salts with α,β-unsaturated aldehydes provides...


2003 ◽  
Vol 2003 (5) ◽  
pp. 258-259 ◽  
Author(s):  
Shou-Ri Sheng ◽  
Lu-Ling Wu ◽  
Xian Huang

Polystyrene-supported (4-phenylseleno)morpholine was synthesised and could be used as an efficient α-selenenylating agent for saturated aldehydes; subsequent oxidation of polystyrene-supported α-selenoaldehydes and the products from the Wittig reaction of them with chloromethylidenetriphenylphosphorane with an excess of 30% hydrogen peroxide at room temperature afforded α,β-unsaturated aldehydes in good yields and purities.


Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>


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