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Amphiphilic Polymer Supports for the Asymmetric Hydrogenation of Amino Acid Precursors in Water
Author(s) -
Zarka M. Tobias,
Nuyken Oskar,
Weberskirch Ralf
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200304729
Subject(s) - copolymer , amphiphile , polymer chemistry , polymer , chemistry , side chain , cinnamic acid , substrate (aquarium) , organic chemistry , oceanography , geology
This paper describes the synthesis and characterization of a new class of amphiphilic, water‐soluble diblock copolymers based on 2oxazoline derivatives with pendent (2 S ,4 S )‐4‐diphenylphosphino‐2‐(diphenylphosphinomethyl)pyrrolidine (PPM) units in the hydrophobic block. The synthetic strategy involves the preparation of a diblock copolymer precursor with ester functionalities in the side chain; which were converted into carboxylic acids in a polymer‐analogous step and finally reacted with the PPM ligand. The structures of the copolymers were characterized by 1 H and 31 P NMR spectroscopy and GPC measurements. Subsequently, these polymers were successfully utilized as a polymeric support for the asymmetric hydrogenation of 1) ( Z )‐ α ‐acetamido cinnamic acid and 2) methyl ( Z )‐ α ‐acetamido cinnamate in water, showing 90 % substrate conversion at 25 °C within 20 minutes at atmospheric H 2 pressure (1 bar) for methyl ( Z )‐ α ‐acetamido cinnamate.