Iridium‐Catalyzed Enantioselective Allylic Substitutions of Racemic, Branched Trichloroacetimidates with Heteroatom Nucleophiles: Formation of Allylic C−O, C−N, and C−S Bonds
作者:Madhawee K. Arachchi、Hien M. Nguyen
DOI:10.1002/adsc.202100575
日期:2021.9.7
branched allylic carbon-heteroatom bonds from racemic, secondary allylic trichloroacetimidates has been developed. The branched allylic substrates undergo dynamic kinetic asymmetric substitution reactions with a number of unactivated anilines and carboxylic acids as well as unactivated aromatic thiols in the presence of a chiral bicyclo[3.3.0]octadiene-ligated iridium catalyst. The allylic C−O, C−N
Ruthenium-Catalyzed Enantioselective Addition of Carboxylic Acids to Allenes
作者:Jiang-Lin Hu、Felix Bauer、Bernhard Breit
DOI:10.1021/acscatal.1c03306
日期:2021.10.1
A ruthenium-catalyzed synthetic method for branched allylic esters via addition of carboxylicacids to allenes is reported. Ligands were designed and prepared based on the Josiphos skeleton, with which the reaction achieved up to 95% yield and up to >99% enantiomeric excess. A deuterium labeling experiment was performed and a plausible mechanism was proposed. Enantiopure lactones of five- and six-membered
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.
Catalytic Asymmetric Synthesis of Chiral Allylic Esters
作者:Jeffrey S. Cannon、Stefan F. Kirsch、Larry E. Overman
DOI:10.1021/ja106685w
日期:2010.11.3
A broadly useful catalytic enantioselective synthesis of branched allylicesters from prochiral (Z)-2-alkene-1-ols has been developed. The starting allylicalcohol is converted to its trichloroacetimidate intermediate by reaction with trichloroacetonitrile, either in situ or in a separate step, and this intermediate undergoes clean enantioselective S(N)2' substitution with a variety of carboxylic acids
Iterative approach to polyketide-type structures: stereoselective synthesis of 1,3-polyols utilizing the catalytic asymmetric Overman esterification
作者:Jörg T. Binder、Stefan F. Kirsch
DOI:10.1039/b708248g
日期:——
An iterative systematic approach to the 1,3-polyol motif has been developed to provide access to all possible stereoisomers by utilizing the catalytic asymmetric Overman esterification for the construction of all stereogenic centres.