Enantioselective Lewis Acid Catalyzed Michael Reactions of Alkylidene Malonates. Catalysis by <i>C</i><sub>2</sub>-Symmetric Bis(oxazoline) Copper(II) Complexes in the Synthesis of Chiral, Differentiated Glutarate Esters
作者:David A. Evans、Tomislav Rovis、Marisa C. Kozlowski、C. Wade Downey、Jason S. Tedrow
DOI:10.1021/ja002246+
日期:2000.9.1
C2-symmetricbis(oxazoline)−Cu(II) complexes 1 catalyze the Mukaiyama Michael reaction of alkylidene malonates and enolsilanes. The use of hexafluoro-2-propanol is essential to induce catalyst turnover. High enantioselectivities are exhibited by bulky alkylidene malonate β-substituents using catalyst 1a. The glutarate ester products are readily decarboxylated to provide chiral 1,5-dicarbonyl synthons
Direct Construction of Quaternary Carbons from Tertiary Alcohols via Photoredox-Catalyzed Fragmentation of <i>tert</i>-Alkyl <i>N</i>-Phthalimidoyl Oxalates
作者:Gregory L. Lackner、Kyle W. Quasdorf、Larry E. Overman
DOI:10.1021/ja408971t
日期:2013.10.16
A convenientmethod for the direct construction of quaternary carbons from tertiary alcohols by visible-light photoredox coupling of tert-alkyl N-phthalimidoyl oxalate intermediates with electron-deficient alkenes is reported.
Synthetic Efforts toward the<i>Lycopodium</i>Alkaloids Inspires a Hydrogen Iodide Mediated Method for the Hydroamination and Hydroetherification of Olefins
作者:Paul R. Leger、Rebecca A. Murphy、Eugenia Pushkarskaya、Richmond Sarpong
DOI:10.1002/chem.201406242
日期:2015.3.9
related natural products. This observation has been expanded into a general method for the room temperature hydroamination of unactivated olefins with tosylamides utilizing catalytic “anhydrous” HI (generated in situ from trimethylsilyl iodide and water). The presence of the iodide anion is critical to the success of this Brønsted acid catalyzed protocol, possibly due to its function as a weakly coordinating
(+)-tricycloclavulone having a unique tricyclo[5,3,0,01,4]decane skeleton and six chiral centers was achieved in a highly stereoselective manner. It includes a catalytic enantioselective [2+2]-cycloadditionreaction using novel chiral copper catalyst, extremely effecting an intramolecular ester transfer reaction, and asymmetric reduction of the carbonyl group on the alpha-chain using Noyori's chiral ruthenium catalyst
In the presence of a catalytic amount of trityl salts, silyl enol ethers of thioesters react with α-substituted α,β-unsaturated cyclic ketones to afford the corresponding Michael adducts in good yields with excellent lk diastereoselectivities.