1408053-96-2Relevant academic research and scientific papers
Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran by a palladium/norbornene-catalyzed ordered reaction sequence
Della Ca, Nicola,Fontana, Marco,Xu, Di,Cremaschi, Mirko,Lucentini, Riccardo,Zhou, Zhi-Ming,Catellani, Marta,Motti, Elena
, p. 6389 - 6401 (2015/08/18)
Abstract Developments are reported in the catalytic synthesis of biaryls containing an ortho-carbaldehyde or 6H-dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o-substituted aryl iodides and o-bromobenzyl alcohols proceeds by unsymmetrical aryl-aryl coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C-O coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH2OH in the other is described along with some mechanistic insights.
A sequential Pd/norbornene-catalyzed process generates o- biaryl carbaldehydes or ketones via a redox reaction or 6 h -dibenzopyrans by C-O ring closure
Motti, Elena,Ca, Nicola Della,Xu, Di,Piersimoni, Anna,Bedogni, Elena,Zhou, Zhi-Ming,Catellani, Marta
supporting information, p. 5792 - 5795 (2013/01/15)
o-Biaryl carbaldeydes and ketones are obtained through the one-pot reaction of o-aryl iodides with o-bromobenzyl alcohols under the catalytic action of Pd and norbornene, in the presence of a base. The same reaction can also give dibenzopyrans by Pd and norbornene catalysis with a different termination, leading to C-O ring closure. In both cases the process first leads to a five-membered palladacycle, which controls C-C coupling, then to a seven-membered oxapalladacycle, which gives aldehydes and ketones or dibenzopyrans.
