Iridium-Catalyzed Kinetic Asymmetric Transformations of Racemic Allylic Benzoates
作者:Levi M. Stanley、Chen Bai、Mitsuhiro Ueda、John F. Hartwig
DOI:10.1021/ja103779e
日期:2010.7.7
Versatile methods for iridium-catalyzed, kinetic asymmetric substitution of racemic, branched allylic esters are reported. These reactions occur with a variety of aliphatic, aryl, and heteroaryl allylic benzoates to form the corresponding allylic substitution products in high yields (74-96%) with good to excellent enantioselectivity (84-98% ee) with a scope that encompasses a range of anionic carbon and heteroatom nucleophiles. These kinetic asymmetric processes occur with distinct stereochemical courses for racemic aliphatic and aromatic allylic benzoates, and the high reactivity of branched allylic benzoates enables enantioselective allylic substitutions that are slow or poorly selective with linear allylic electrophiles.
The oxidation of derivatives of malononitrile with peracid in methanol proceeds with loss of the cyano groups to yield methyl esters in high yield. The method was applied to a variety of malononitrile derivatives, some of which were prepared by Pd- or Ir-catalyzed asymmetric allylic substitution.
在甲醇中用过酸对丙二腈衍生物进行氧化,同时失去氰基,以高产率得到甲酯。该方法应用于多种丙二腈衍生物,其中一些是通过 Pd 或 Ir 催化的不对称烯丙基取代制备的。
Cobalt-Catalyzed Regio- and Enantioselective Allylic Alkylation of Malononitriles
作者:Samir Ghorai、Sajid Ur Rehman、Wen-Bin Xu、Wen-Yu Huang、Changkun Li
DOI:10.1021/acs.orglett.0c00962
日期:2020.5.1
Cobalt-catalyzed highly branched- and enantioselectiveallylicalkylation of malononitriles has been developed. Chiral γ,δ-unsaturated malononitriles could be synthesized with >20:1 branched/linear regioselectivity and up to 99% enantiomeric excess from easily accessible racemic allylic carbonates under mild reaction conditions. The electron-rich and sterically less hindered bisoxazolinephosphine ligand