9-Amino-(9-deoxy)cinchona alkaloid-derived new chiral phase-transfer catalysts
作者:Wenwen Peng、Jingwei Wan、Bing Xie、Xuebing Ma
DOI:10.1039/c4ob01648c
日期:——
9-amino-(9-deoxy)cinchona alkaloid-derived chiralphase-transfercatalysts bearing amino groups was developed by using known cinchona alkaloids as the starting materials. Due to the transformation of the 9-hydroxyl group into a 9-amino functional group, the catalytic performances were significantly improved in comparison with the corresponding first generation phase-transfercatalysts, and excellent yields (92–99%)
was used in phase-transfer alkylations and Michael additions to afford various opticallyactive α-amino acid equivalents in up to 93% yield. Moreover, dramatic counter anion effects were observed in phase-transfer catalysis (PTC) for the first time, making it possible to further improve reactivity and selectivity. These findings validate the usefulness of three-dimensional fine-tuning of the catalyst
Design of new, chiral phase-transfer catalysts for practical, catalytic asymmetric synthesis
作者:Keiji Maruoka
DOI:10.1016/s0022-1139(01)00472-9
日期:2001.11
Structurally rigid, chiral spiro ammonium salts of type 1 derived from commercially available (S)-binaphthol have been designed as a new C2-symmetricchiralphase-transfercatalyst and successfully applied to the highly efficient, catalytic enantioselective alkylation of tert-butyl glycinate Schiff base under mild phase-transfer conditions to furnish α-alkyl-α-amino acids and α,α-dialkyl-α-amino acids with excellent
Amide-Based <i>Cinchona</i> Alkaloids as Phase-Transfer Catalysts: Synthesis and Potential Application
作者:Maciej Majdecki、Patryk Niedbala、Janusz Jurczak
DOI:10.1021/acs.orglett.9b03065
日期:2019.10.4
easily and efficiently from inexpensive and commercially available substrates. We tested this class of alkaloids in the alkylation of glycine derivative, carried out under phase-transfercatalyst conditions. The presented hybrid catalysts offer both high reaction yields (up to 97%) and high enantioselectivities of the obtained product (up to 94% ee).
A novel class of tartaric acid-derived N-spiro quaternary ammonium salts was synthesised starting from known TADDOLs. These compounds were found to catalyse the asymmetric α-alkylation of glycine Schiff bases with high enantioselectivities and in good yields.