ISSN:
1573-9171
Keywords:
Pd catalysts on chiral polymers
;
asymmetric reduction
;
azlactones
;
reductive aminolysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Pd complexes have been obtained from linear and cross-linked copolymers ofR,S-, R-, andS-1-(4-vinylphenyl)ethylamine (1) with styrene and divinylbenzene. Reduction of these compounds gave catalysts which were active in the reductive solvolysis of α-acetaminocinnamic acid azlactone (2) and hydrogenation of the solvolysis products α-acetamidocinnamic acid (ACA), its esters, and its 1-phenylethylamide. The catalysts showed no enantioselective properties in the reductive hydrolysis, but were more active than the catalyst obtained in the absence of the polymer (the “monomeric” analog). The use of polymeric catalysts has shown that, in reductive aminolysis, the chiral nucleophile plays the dominant part in determining the stereoselectivity of the reaction, rather than the chiral ligand of the catalytic complex. The polymer matrix stabilizes the low-valent state of the palladium in the complex. In the hydrogenation of ACA and its esters, the catalyst on the cross-linked polymer is much more active than its “monomeric” analog, but showed no enantioselectivity. Hydrogenation of acetamidocinnamic acidR-andS-1-phenylethylamides on a chiral Pd-polymer catalyst occurred with double asymmetric induction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00863823
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