Asymmetric Michael addition reactions of 2-silyloxyfurans catalyzed by binaphthyldiimine–Ni(<scp>ii</scp>) complexes
作者:Hiroyuki Suga、Takeo Kitamura、Akikazu Kakehi、Toshihide Baba
DOI:10.1039/b402826k
日期:——
ene)-1,1'-binaphthyl-2,2'-diamine-Ni(II) complex and analogous complexes were found to be efficient chiral Lewis acid catalysts for the asymmetricMichael addition reactions between 2-silyloxyfurans and 3-alkenoyl-2-oxazolidinones, for which asymmetricinductions of up to 97% ee were obtained.
Asymmetric Vinylogous Mannich Reaction of Silyloxy Furans with <i>N</i>-<i>tert</i>-Butanesulfinyl Ketimines
作者:V. U. Bhaskara Rao、Amol P. Jadhav、Dnyaneshwar Garad、Ravi P. Singh
DOI:10.1021/ol4037117
日期:2014.2.7
A highly regio- and diastereoselective TMSOTf promoted vinylogousMannichreaction for the synthesis of chiral quaternary 3-aminooxindole butenolides from 2-silyloxy furans and chiral ketimines is described. The method is found to be very efficient and also provides a facile access to sterically challenging 3-aminooxindole butenolides bearing two quaternary centers in continuation. Further, the versatility
Unravelling the Nucleophilicity of Butenolides for 1,6-Conjugate Addition to <i>p</i>-Quinone Methides: A Direct Access to Diversely Substituted Butenolide-Derived Diarylmethanes
作者:Brijesh M. Sharma、Dinesh R. Shinde、Ruchi Jain、Eeshwaraiah Begari、Shruti Satbhaiya、Rajesh G. Gonnade、Pradeep Kumar
DOI:10.1021/acs.orglett.8b00745
日期:2018.5.4
A Lewis acid catalyzed regioselective C-C bond is constructed through beta-addition of deconjugated butenolides with p-quinone methides in a 1,6-conjugate addition manner. Interestingly, Lewis acid catalyzed vinylogous Mukaiyama-Michael reaction of silyloxyfurans with p-QMs proceeds selectively through the alpha or gamma position exclusively. The reaction is mild with broad substrate scope, thus allowing easy access to a wide range of bis-arylated alpha-/beta-/gamma-substituted butenolides.