ISSN:
0025-116X
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
Graft polymerization of various vinyl monomers onto a polystyrene resin (6) containing azo groups having the ability to initiate the radical polymerization was performed. The graft efficiency of vinyl monomers onto 6 increases with time of polymerization and achieves more than 85%. The swelling of 6 affects remarkably the graft efficiency. Scanning electron microscopy (SEM) shows that considerable amounts of graft copolymers are located at the surface of 6. The graft copolymer of chloromethylstyrene onto 6 was treated with (S)-(-)-2-amino-3-(p-hydroxyphenyl)-1,1-diphenyl-1-propanol to yield a resin (9) carrying chiral amino alcohol functions. Resin 9/borane was used for asymmetric reductions of acetophenone oxime O-methyl and O-benzyl ethers, leading to 1-phenylethylamine with 43% and 46% enantiomeric excess (e.e.), respectively. These values are higher than those obtained with the generally used polystyrene resin, suggesting that the enantioselectivity can be improved by modification of the support resin.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/macp.1989.021901210
Permalink