Facile Synthesis of Versatile Enantioenriched α-Substituted Hydroxy Esters through a Brønsted Acid Catalyzed Kinetic Resolution
作者:Ghassan Qabaja、Jennifer E. Wilent、Amanda R. Benavides、George E. Bullard、Kimberly S. Petersen
DOI:10.1021/ol400207t
日期:2013.3.15
An efficient synthesis of enantioenriched α-substituted γ-hydroxy esters via a kinetic resolution event is described. Bulky racemic esters in the presence of a chiral Brønsted acid selectively lactonize to yield a recoverable enantioenriched hydroxy ester and lactone. These esters are highly versatile building blocks that can readily be converted to synthetically useful materials.
Unexpected Electrophilic Rearrangements of Amides: A Stereoselective Entry to Challenging Substituted Lactones
作者:Claire Madelaine、Viviana Valerio、Nuno Maulide
DOI:10.1002/anie.200906416
日期:2010.2.22
Surprise, surprise! An unexpected skeletal rearrangement was developed into a chemo‐ and stereoselective synthesis of α‐allyl and allenyl lactones with challenging substitution patterns (see scheme; EWG=electron‐withdrawing group). The generality, unique features, and synthetic potential of this reaction were probed and a mechanism was proposed.
Copper‐Catalyzed Enantioselective Allylic Alkylation with a γ‐Butyrolactone‐Derived Silyl Ketene Acetal
作者:Carina I. Jette、Z. Jaron Tong、Ryan G. Hadt、Brian M. Stoltz
DOI:10.1002/anie.201912618
日期:2020.1.27
Herein, we report a Cu-catalyzed enantioselective allylic alkylation using a γ-butyrolactone-derived silylketeneacetal. Critical to the development of this work was the identification of a novel mono-picolinamide ligand with the appropriate steric and electronic properties to afford the desired products in high yield (up to 96 %) and high ee (up to 95 %). Aryl, aliphatic, and unsubstituted allylic
The Tsuji–Trost protocol has been successfully employed for the allylicalkylation of preformed lactone enolates. It has been demonstrated that this Pd‐catalyzed reaction can be carried out in an enantio‐ and diastereoselective manner. The use of additives, such as LiCl, was found to be crucial for reaching high levels of product selectivity. For one particular pair of reactants, density functional