Enantioselective Addition of Boronates to Acyl Imines Catalyzed by Chiral Biphenols
作者:Joshua A. Bishop、Sha Lou、Scott E. Schaus
DOI:10.1002/anie.200901023
日期:2009.6.2
On the big screen: A chiralbiphenol catalyst screening protocol was developed for the rapid identification of enantioselective nucleophilic boronate reactions with acylimines (see scheme). The approach successfully identified a unique catalyst for the reaction of aryl, vinyl, and alkynyl boronates. Mechanistic studies demonstrate boronate ligand exchange with the catalyst is necessary for activation
An efficient synthesis of trisubstituted oxazoles via chemoselective O-acylations and intramolecular Wittig reactions
作者:Yi-Ling Tsai、Yu-Shiou Fan、Chia-Jui Lee、Chan-Hui Huang、Utpal Das、Wenwei Lin
DOI:10.1039/c3cc45883k
日期:——
Preparation of new types of trisubstituted oxazoles is realized via chemoselective O-acylations and intramolecular Wittig reactions with ester functionalities using in situ formed phosphorus ylides as key intermediates. A plausible reaction mechanism for this undiscovered chemistry is also proposed based on the existence of expected and rearranged isomeric oxazoles.
Diastereo- and Enantioselective Addition of Anilide-Functionalized Allenoates to <i>N</i>-Acylimines Catalyzed by a Pyridylalanine-Based Peptide
作者:Curren T. Mbofana、Scott J. Miller
DOI:10.1021/ja412996f
日期:2014.2.26
A selective peptide-catalyzed addition of allenic esters to N-acylimines is reported. Tetrasubstituted allenes were achieved with up to 42:1 diastereomeric ratio and 94:6 enantiomeric ratio (up to 99:1 er after recrystallization of the major diastereomer). An exploration of the role of individual amino acids within the peptide was undertaken. The scope of the reaction was explored and revealed heightened reactivity with thioester-containing allenes. A mechanistic framework that may account for the observed reactivity is also described.