Recoverable Dendritic Phase-Transfer Catalysts that Contain (+)-Cinchonine-Derived Ammonium Salts
作者:Jordi Rull、José Juan Jara、Rosa M. Sebastián、Adelina Vallribera、Carmen Nájera、Jean-Pierre Majoral、Anne-Marie Caminade
DOI:10.1002/cctc.201600283
日期:2016.6.21
The asymmetric alkylation of a glycinate Schiff base with benzyl bromide is used as a benchmark reaction, and the dendrimeric catalyst that contains an allyl group on the O‐9 hydroxy group of the cinchonine units is the most active. The recovery and reuse of the catalyst are possible for five consecutive runs without loss of activity and with only a slight decrease in enantioselectivity. If other electrophiles
<i>N-</i>Arylation of Amino Acid Esters to Expand Side Chain Diversity in Ketoxime Peptide Ligations
作者:Hailey A. Young、Quibria A. E. Guthrie、Caroline Proulx
DOI:10.1021/acs.joc.9b02810
日期:2020.2.7
N-arylations of aminoacid tert-butyl esters using 4-bromo-N,N-dimethylaniline as a coupling partner are reported. The resulting N-aryl aminoacid esters are suitable building blocks for the synthesis of electron-rich N-aryl peptides, which undergo oxidative couplings to aminooxy groups to afford ketoxime peptides under mild conditions. N-aryl aminoacid tert-butyl esters possessing unnatural side chains