(S)-Mandelic acid enolate as a chiral benzoyl anion equivalent for the enantioselective synthesis of non-symmetrically substituted benzoins
作者:Gonzalo Blay、Isabel Fernández、Belén Monje、Marc Montesinos-Magraner、José R. Pedro
DOI:10.1016/j.tet.2010.12.012
日期:2011.2
A strategy for the enantioselective synthesis of non-symmetrically substituted benzoins from (S)-mandelic acid and aromatic aldehydes has been developed. This strategy is based on a diastereoselective aldol reaction of the lithium enolate of the 1,3-dioxolan-4-one derived from (S)-mandelic acid and pivalaldehyde with aromatic aldehydes, which gives the corresponding aldols in good yields. Subsequent
Metallophosphites as Umpolung Catalysts: The Enantioselective Cross Silyl Benzoin Reaction
作者:Xin Linghu、Justin R. Potnick、Jeffrey S. Johnson
DOI:10.1021/ja0496468
日期:2004.3.1
metallophosphites as catalysts. As a result, nonenzymatic asymmetric cross silyl benzoin reactions have been achieved, giving optically active silyl ether-protected benzoin adducts. The reaction is general with respect to aryl, alkyl, and heterocyclic substrates with good to excellent yields and good to excellent enantioselectivities.
New Umpolung Catalysts: Reactivity and Selectivity of Terpenol-Based Lithium Phosphonates in Enantioselective Benzoin-Type Couplings
作者:Anca Gliga、Helge Klare、Maria Schumacher、Francis Soki、Jörg M. Neudörfl、Bernd Goldfuss
DOI:10.1002/ejoc.201001295
日期:2011.1
Two newclasses of terpenol-based lithium phosphonates, i.e. phenylfenchyl phosphonates and 2,2'-biphenyldiylbis(terpenyl) phosphonates, are employed as umpolung catalysts for the enantioselective cross benzoin coupling. The structural characteristics of the phosphonates were investigated by means of X-ray, 31 P-NMR analyses as well as DFT computations. The chiral lithium phosphonates were found to