24133-56-0Relevant academic research and scientific papers
Ring Closing Metathesis Approach for the Synthesis of o-Terphenyl Derivatives
Karmakar, Shilpi,Mandal, Tirtha,Dash, Jyotirmayee
, p. 5916 - 5924 (2019/08/21)
A linear synthesis of o-terphenyl derivatives has been delineated using ring closing metathesis (RCM) as the key step. In this approach, benzil derivatives upon allyl Grignard addition provides diphenyl-1,2-diallyl dihydroxy derivatives which undergo ring closing metathesis to afford tetrahydro terphenyl derivatives. Aromatization-driven dehydration then leads to a diverse set of electron rich and electron deficient o-terphenyls. Furthermore, oxidative coupling of electron rich o-terphenyls provides the corresponding triphenylene derivatives.
Synthesis of heterodinuclear hemisalen complexes on a hexaarylbenzene scaffold and their application for the cross-pinacol coupling reaction
Miyasaka, Akihiro,Amaya, Toru,Hirao, Toshikazu
, p. 1615 - 1621 (2014/03/21)
Intermolecular cross-pinacol coupling reaction between aliphatic and aromatic aldehydes by using heterodinuclear hemisalen complexes 1cis with vanadium(V) and titanium(IV) on a hexaarylbenzene scaffold is reported. Our ligand design is based on the individual activation of two aldehydes by vanadium and titanium, which are positioned with a suitable space on the rigid scaffold. Ligands such as 1cis were synthesized by Diels-Alder addition and decarbonylation reaction, followed by condensation of dialdehyde 3cis with various aminophenols. The influence of the substituents on the ligands on the pinacol coupling reaction was investigated. As a result, the reductive coupling reaction between aliphatic and aromatic aldehydes by using a catalytic amount of 1cis in the presence of Me3SiCl and Zn provided the corresponding cross-coupled 1,2-diol in good yields with high cross-selectivity. Working together: Dihemisalen ligands on a hexaaryl benzene scaffold were designed and the heterodinuclear complexes 1cis with vanadium(V) and titanium(IV) were synthesized from the corresponding disalicylaldehyde compound (see scheme). By using the heterodinuclear catalysts, the selective intermolecular cross-pinacol coupling reaction between aliphatic and aromatic aldehydes is demonstrated. Copyright
Magnesium-mediated carbon-carbon bond formation in aqueous media: Barbier-Grignard allylation and pinacol coupling of aldehydes
Zhang, Wen-Chun,Li, Chao-Jun
, p. 3230 - 3236 (2007/10/03)
Magnesium-mediated Barbier-Grignard type alkylation of aldehydes with alkyl halides was studied in aqueous media. The reaction of aromatic aldehydes with allyl halides is highly effective with either THF or water as the reaction solvent but poor in a mixture of THF/water. It was found that the magnesium-mediated allylation of aldehydes with allyl bromide and iodide proceeds effectively in aqueous 0.1 N HCl or 0.1 N NH4Cl. Aromatic aldehydes reacted chemoselectively in the presence of aliphatic aldehydes. An exclusive selectivity was also observed when both aliphatic and aromatic aldehyde functionalities are present in the same molecule. In the absence of allyl halides, aldehydes and ketones reacted with magnesium in aqueous 0.1 N NH4Cl to form the corresponding pinacol coupling products in high yields. The effectiveness of the pinacol reaction was strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic aldehydes and simple alkyl halides appear inert under the reaction conditions for either alkylation or the pinacol coupling reaction.
