Abstract
The heterogeneous catalytic hydrogenations of 2,2′-pyridoin and related compounds, such as 2,2′-pyridil and O-acetyl-2,2′-pyridoin, were investigated over noble metal catalysts. The influence of catalytic metals, catalyst supports, solvents, acid additives, prehydrogenation, and hydrogen pressure on the chemo- and diastereoselectivity is discussed in the hydrogenation of 2,2′-pyridoin. Although hydrogenolysis and ring saturation may occur as side reactions, high chemo- (90-100%) and moderate diastereoselectivity values were achieved. Over palladium black in an acetonitrile-water solvent mixture, the hydrogenation resulted in a meso/dl ratio of 72/28, while in the hydrogenation over rhodium on carbon the meso/dl ratio was 29/71. The phenomenon of diastereoselection in the hydrogenation is explained by the stereochemistry of the hydrogen addition, considering the cis-trans isomerization on the catalyst surface, the possible enolization, and the competing C=C and C=O reductions.
| Original language | English |
|---|---|
| Pages (from-to) | 472-479 |
| Number of pages | 8 |
| Journal | Journal of Catalysis |
| Volume | 209 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2002 |
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Keywords
- C=C and C=O double bonds
- cis-trans isomerization
- Diastereoselectivity
- Heterogeneous catalytic hydrogenation
- Hydrogenolysis
ASJC Scopus subject areas
- Catalysis
- Process Chemistry and Technology
Cite this
Chemo- and diastereoselectivity in the heterogeneous catalytic hydrogenation of 2,2′-pyridoin and its derivatives. / Háda, Viktor; Tungler, A.; Szepesy, L.
In: Journal of Catalysis, Vol. 209, No. 2, 2002, p. 472-479.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Chemo- and diastereoselectivity in the heterogeneous catalytic hydrogenation of 2,2′-pyridoin and its derivatives
AU - Háda, Viktor
AU - Tungler, A.
AU - Szepesy, L.
PY - 2002
Y1 - 2002
N2 - The heterogeneous catalytic hydrogenations of 2,2′-pyridoin and related compounds, such as 2,2′-pyridil and O-acetyl-2,2′-pyridoin, were investigated over noble metal catalysts. The influence of catalytic metals, catalyst supports, solvents, acid additives, prehydrogenation, and hydrogen pressure on the chemo- and diastereoselectivity is discussed in the hydrogenation of 2,2′-pyridoin. Although hydrogenolysis and ring saturation may occur as side reactions, high chemo- (90-100%) and moderate diastereoselectivity values were achieved. Over palladium black in an acetonitrile-water solvent mixture, the hydrogenation resulted in a meso/dl ratio of 72/28, while in the hydrogenation over rhodium on carbon the meso/dl ratio was 29/71. The phenomenon of diastereoselection in the hydrogenation is explained by the stereochemistry of the hydrogen addition, considering the cis-trans isomerization on the catalyst surface, the possible enolization, and the competing C=C and C=O reductions.
AB - The heterogeneous catalytic hydrogenations of 2,2′-pyridoin and related compounds, such as 2,2′-pyridil and O-acetyl-2,2′-pyridoin, were investigated over noble metal catalysts. The influence of catalytic metals, catalyst supports, solvents, acid additives, prehydrogenation, and hydrogen pressure on the chemo- and diastereoselectivity is discussed in the hydrogenation of 2,2′-pyridoin. Although hydrogenolysis and ring saturation may occur as side reactions, high chemo- (90-100%) and moderate diastereoselectivity values were achieved. Over palladium black in an acetonitrile-water solvent mixture, the hydrogenation resulted in a meso/dl ratio of 72/28, while in the hydrogenation over rhodium on carbon the meso/dl ratio was 29/71. The phenomenon of diastereoselection in the hydrogenation is explained by the stereochemistry of the hydrogen addition, considering the cis-trans isomerization on the catalyst surface, the possible enolization, and the competing C=C and C=O reductions.
KW - C=C and C=O double bonds
KW - cis-trans isomerization
KW - Diastereoselectivity
KW - Heterogeneous catalytic hydrogenation
KW - Hydrogenolysis
UR - http://www.scopus.com/inward/record.url?scp=57249110662&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=57249110662&partnerID=8YFLogxK
U2 - 10.1006/jcat.2002.3652
DO - 10.1006/jcat.2002.3652
M3 - Article
AN - SCOPUS:57249110662
VL - 209
SP - 472
EP - 479
JO - Journal of Catalysis
JF - Journal of Catalysis
SN - 0021-9517
IS - 2
ER -