Highly
<i>E</i>
‐Selective and Enantioselective Michael Addition to Electron‐Deficient Internal Alkynes Under Chiral Iminophosphorane Catalysis
作者:Daisuke Uraguchi、Kohei Yamada、Takashi Ooi
DOI:10.1002/anie.201503928
日期:2015.8.17
A highly E‐selective and enantioselective conjugate addition of 2‐benzyloxythiazol‐5(4H)‐ones to β‐substituted alkynyl N‐acyl pyrazoles is achieved under the catalysis of a P‐spiro chiral iminophosphorane. Simultaneous control of the newly generated central chirality and olefin geometry is possible with a wide array of the alkynyl Michael acceptors possessing different aromatic and aliphatic β‐substituents
A highlystereoselective Michael addition of α-amino acid-derived 2-benzyloxythiazol-5(4H)-ones to dimethyl allenedicarboxylate was developed by employing P-spiro chiral triaminoiminophosphorane bearing (S)-sec-butyl groups as a catalyst. Theoretical investigation of the transition-state models for the reaction and control experiments suggested the intervention of a dynamickineticresolution of the