A Simple Tetraminocalix[4]arene as a Highly Efficient Catalyst under “On-Water” Conditions through Hydrophobic Amplification of Weak Hydrogen Bonds
作者:Margherita De Rosa、Pellegrino La Manna、Annunziata Soriente、Carmine Gaeta、Carmen Talotta、Neal Hickey、Silvano Geremia、Placido Neri
DOI:10.1002/chem.201701247
日期:2017.5.23
simple tetraminocalix[4]arene 1, which contains weak H‐bond‐donor NH2 groups, is reported to be a highly efficient organocatalyst for the Vinylogous Mukaiyama Aldol Reaction (VMAR) of 2‐(trimethylsilyloxy)furan 5 with α‐ketoesters 6 a–l under “on‐water” conditions owing to the hydrophobic amplification of weak H‐bond interactions. The catalytic efficiency of calixarene catalyst 1 was shown to be closely
In control: A new catalytic vinylogousMukaiyamaaldolreaction provides products with high diastereo‐ and enantioselectivities (up to 99 % de and ee; see scheme). The relative and absolute stereochemistry of a representative product was rigorously assigned by NMR and CD spectroscopies (measured and calculated), X‐ray diffraction, and quantum‐chemical calculations.