palladium-catalyzed cross-coupling of o-allylic and o-vinylic phenols with vinylic halides and triflates produces substituted dihydrobenzopyrans and dihydrobenzofurans respectively in good to high yields. The proposed mechanism involves vinylpalladium addition to the olefin, rearrangement to a π-allylpalladium intermediate and subsequent intramolecular nucleophilic displacement of palladium.
Water: A Suitable Medium for the Petasis Borono-Mannich Reaction
作者:Nuno R. Candeias、Luís F. Veiros、Carlos A. M. Afonso、Pedro M. P. Gois
DOI:10.1002/ejoc.200900056
日期:——
Water was used as the solvent in the Petasisborono-Mannichreaction. With the use of salicylaldehyde, secondary amines and boronic acids, several alkylaminophenols were obtained in considerably high yields in water. By using the same methodology, 2H-chromenes were prepared with the use of vinyl boronic acids. The reaction mechanism was studied by DFT calculations, and the results obtained corroborate