Heteroarylation of anthraquinone-triflate by suzuki cross-coupling

A Stereospecific, Intermolecular Biaryl-Coupling Approach to Korupensamine A En Route to the Michellamines

“…The resting state of the catalyst was established as a mixture of the Co I bis-olefin complex and the Co III dialkyl carbonyl complex whose ratio is dependent on the substrate structures and concentrations [Eq. [12] Reductive elimination [12,13] When n-butyraldehyde was used as the substrate traces of isobutyraldehyde were evident near complete conversion of aldehyde, which indicated some reversibility prior to the reductive elimination of ketone.…”

Nanostructured Pyrophosphate Na2PdP2O7‐Catalyzed Suzuki‐Miyaura Cross‐Coupling Under Microwave Irradiation

“…Indeed, the reaction conducted with 2 ml of water produced the corresponding product in 95% yield. The decrease of the yield could be attributed to the dispersion of the reagents when a large volume of water is used, or it can also be attributed to the protodeboronation of the boronic acids in water as no side product was detected . The tendency to protodeboronate quite often manifests itself during cross‐coupling reactions carried out in polar protic solvents and influences the stoichiometry of the reaction.…”

A Stereospecific, Intermolecular Biaryl-Coupling Approach to Korupensamine A En Route to the Michellamines

“…[12,13] When n-butyraldehyde was used as the substrate traces of isobutyraldehyde were evident near complete conversion of aldehyde, which indicated some reversibility prior to the reductive elimination of ketone. [12] Reductive elimination with the second row rhodium analogues should exhibit higher energy barriers than the cobalt complexes; thus rhodium analogues may exhibit more extensive reversibility and have the potential to isomerize aldehydes prior to ketone formation. [14,15] Indeed, we report here that rhodium(i) olefin complexes of the type [C 5 Me 5 Rh(C 2 H 3 R) 2 ] catalyze the interconversion of linear and branched aldehydes as well as transfer formylation reactions.…”

“…[11] However, it was essential in this case to use a boronate (12; Scheme 4), rather than the precursor boronic acid, which has good hydrolytic stability due to the presence of the OTIPS residue in this molecule. successful, did not translate to the ªrealº system, and revealed a critical need for 2,6-di-tert-butyl-4-methylphenol (BHT; 0.7 equiv) [12] in the reaction medium (DMF). The coupling of iodide 9 with 12 occurred efficiently under these modified conditions (81 %; Scheme 5), but the 5:4 ratio of S(P):R(M) atropisomers obtained indicated that steric factors alone at each hydroxymethyl site in 1 and 2 (R L TIPS) are not sufficient for high diastereocontrol in the biaryl forming step.…”

“…(2)]. [12,13] When n-butyraldehyde was used as the substrate traces of isobutyraldehyde were evident near complete conversion of aldehyde, which indicated some reversibility prior to the reductive elimination of ketone. [12] Reductive elimination…”