Activation of Alcohols with Carbon Dioxide: Intermolecular Allylation of Weakly Acidic Pronucleophiles
作者:Simon B. Lang、Theresa M. Locascio、Jon A. Tunge
DOI:10.1021/ol502023d
日期:2014.8.15
coupling of allyl alcohols with nitroalkanes, nitriles, and aldehydes using catalytic Pd(PPh3)4 has been accomplished viaactivation of C–OH bonds with CO2. The in situ formation of carbonates from alcohols and CO2 facilitates oxidativeaddition to Pd to form reactive π-allylpalladium intermediates. In addition, the formation of a strong baseactivates nucleophiles toward the reaction with the π-allylpalladium
clean method has been developed for the α‐allylation of phenyl and alpha alkyl phenyl acetonitrile with allylic alcohols. The reaction is catalyzed by nickel complexes in situ generated from a combination of Ni(cod)2 and the dppf ligand and performed at 80 °C in methanol as reaction solvent. Accordingly to this simple and base‐free protocol that only yields water as a side‐product, many allylic nitriles
A novel chiral yttrium complex with a tridentate linked amido-indenyl ligand for intramolecular hydroamination
作者:Zhuo Chai、Dezhi Hua、Kui Li、Jiang Chu、Gaosheng Yang
DOI:10.1039/c3cc47006g
日期:——
A new chiral silicon-linked tridentate amido-indenyl ligand was developed from indene and enantiopure 1,2-cyclohexanediamine. Its yttrium complex was synthesized, characterized and applied to efficiently catalyze the intramolecular hydroamination of non-activated olefins with up to 97% ee.
The in situ preparation of chiral amido alkyl ate yttrium complexes from an array of chiral N-benzyl-like-substituted binaphthyldiamines is reported. These chiral heteroleptic complexes are shown to be efficient catalysts for the enantioselective intramolecular hydroamination of primary amines tethered to sterically demanding alkenes at high reaction temperatures. Fine tuning of their chiral environment allowed up to 77% ee to be reached for the cyclization of aminoalkenes bearing 1,2-dialkyl-substituted carbon-carbon double bonds. These chiral complexes also demonstrate the ability to promote the cyclization of amine-tethered trisubstituted alkenes in up to 55% ee, as the first report of the formation of enantioenriched quaternary centers by an hydroamination reaction.