Ortega-Martínez, Aitor, Lorenzo, Rocco de, Sansano, Jose M., Nájera, Carmen
Palladium-catalyzed allylation and deacylative allylation of 3-acetyl-2-oxindoles with allylic alcohols
Tetrahedron. 2018, 74(2): 253-259. doi:10.1016/j.tet.2017.11.041
URI: http://hdl.handle.net/10045/72136
DOI: 10.1016/j.tet.2017.11.041
ISSN: 0040-4020 (Print)
Abstract: 
The Pd-catalyzed allylation of 3-acetyl-2-oxindoles with allyl alcohol is performed using 3 mol% of Pd(dba)2, rac-BINAP and BINOL phosphoric acid as catalytic mixture. This procedure allows the in situ synthesis of 3-allyl-2-oxindole by adding Triton B to the reaction mixture. The deacylative allylation of 3-acetyl-3-methyl-2-oxindoles with allylic alcohols is carried out with 3 mol% of Pd(OAc)2, dppp and 1.5 equiv. of LiOtBu as base affording the corresponding 3,3-disubstituted 2-oxindoles in good yields. Both methodologies can be combined for the preparation of unsymmetrical 3,3-diallylated 2-oxindoles such as compound 7. The DaA must be carried out in the absence of oxygen in order to avoid the competitive formation of 3-alkyl-3-hydroxy-2-indoles. The later compounds can be easily obtained by deacylative oxidation of 3-alkylated 3-acetyl-2-oxindoles with LiOEt at rt under air.
Keywords:Oxindoles, Allylic alcohols, Palladium, Catalysis, Deacylation
Elsevier
info:eu-repo/semantics/article