ISSN:
0947-6539
Schlagwort(e):
catalysis
;
dehydrogenations
;
oxidations
;
ruthenium complexes
;
secondary alcohols
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Highly efficient ruthenium-catalyzed Oppenauer-type oxidations of secondary alcohols to ketones have been developed. The catalytic system consists of [(PPh3)3RuCl2] (1) and K2CO3 or [(C4Ph4COHOCC4Ph4)(μ-H)(CO)4Ru2] (2) in refluxing acetone. The catalytic reaction is of high efficiency and permits a catalyst: substrate ratio of 1:1000 at 56 °C. In some cases the initial turnover rate exceeds 1500 h-1. The reaction was found to be general and compatible with double bonds and oxidation-sensitive aromatics. With some allylic alcohols, isomerization to saturated ketones took place. The reaction proceeds by ruthenium-catalyzed dehydrogenation of the alcohol and subsequent hydrogen transfer to acetone. No primary kinetic isotope effect was observed for the catalytic reaction when α-deuterated 1-phenylethanol was employed as substrate (kH/kD=1.1); this shows that β-hydride elimination from a ruthenium alkoxide intermediate is not the rate-limiting step.
Zusätzliches Material:
1 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/chem.19960021210
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