Construction of bispirooxindoles containing three quaternary stereocentres in a cascade using a single multifunctional organocatalyst
作者:Bin Tan、Nuno R. Candeias、Carlos F. Barbas
DOI:10.1038/nchem.1039
日期:2011.6
Single-step constructions of molecules with multiple quaternary carbon stereocentres are rare. The spirooxindole structural motif is common to a range of bioactive compounds; however, asymmetric synthesis of this motif is complicated due to the presence of multiple chiral centres. The development of organocatalytic cascade reactions has proven to be valuable for the construction of several chiral centres
BF<sub>3</sub>·OEt<sub>2</sub> catalyzed chemoselective CC bond cleavage of α,β-enones: an unexpected synthesis of 3-alkylated oxindoles and spiro-indolooxiranes
作者:Sengodagounder Muthusamy、Ammasi Prabu
DOI:10.1039/d1ob02002a
日期:——
of α,β-enones with diazoamides for the synthesis of 3-alkylated oxindoles is developed. Borontrifluoride etherate is found to be an effectivecatalyst for the chemoselective Cα–Cβ cleavage of enones to obtain 3-alkylated oxindoles. The product formation indicates a selective β-carbon elimination pathway of α,β-enones using the inexpensive BF3·OEt2 as a catalyst, transition metal-free conditions, an