Abstract
Highly enantioselective hydrogenation of 1,4,5,6-tetrahydropyrazine-2- (N-tert-butyl)carboxamide (2) was accomplished by a rhodium complex coordinated with a chiral diphosphine TRAP ligand, which is possible to chelate to a transition metal atom in a trans-manner. Of particular interest is that (R,R)-(S,S)-i-BuTRAP gave 97% ee of the corresponding piperazine-2- carboxylic acid derivative (3) with (S) configuration, while the hydrogenation with (R,R)-(S,S)-MeTRAP-rhodium catalyst provided (R)-3 with up to 85% ee. 31P NMR studies of behavior of i-Bu- and MeTRAP-rhodium catalysts during the reaction suggest that the asymmetric hydrogenation of 2 with TRAPs may involve two competitive reaction pathways, giving their respective enantiomeric products 3.
| Original language | English |
|---|---|
| Pages (from-to) | 1232-1237 |
| Number of pages | 6 |
| Journal | Journal of Organic Chemistry |
| Volume | 64 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Feb 19 1999 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Organic Chemistry
Cite this
Asymmetric hydrogenation of 1,4,5,6-tetrahydropyrazine-2-(N-tert- butyl)carboxamide catalyzed by trans-chelating chiral diphosphine-rhodium complexes. / Kuwano, Ryoichi; Ito, Y.
In: Journal of Organic Chemistry, Vol. 64, No. 4, 19.02.1999, p. 1232-1237.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Asymmetric hydrogenation of 1,4,5,6-tetrahydropyrazine-2-(N-tert- butyl)carboxamide catalyzed by trans-chelating chiral diphosphine-rhodium complexes
AU - Kuwano, Ryoichi
AU - Ito, Y.
PY - 1999/2/19
Y1 - 1999/2/19
N2 - Highly enantioselective hydrogenation of 1,4,5,6-tetrahydropyrazine-2- (N-tert-butyl)carboxamide (2) was accomplished by a rhodium complex coordinated with a chiral diphosphine TRAP ligand, which is possible to chelate to a transition metal atom in a trans-manner. Of particular interest is that (R,R)-(S,S)-i-BuTRAP gave 97% ee of the corresponding piperazine-2- carboxylic acid derivative (3) with (S) configuration, while the hydrogenation with (R,R)-(S,S)-MeTRAP-rhodium catalyst provided (R)-3 with up to 85% ee. 31P NMR studies of behavior of i-Bu- and MeTRAP-rhodium catalysts during the reaction suggest that the asymmetric hydrogenation of 2 with TRAPs may involve two competitive reaction pathways, giving their respective enantiomeric products 3.
AB - Highly enantioselective hydrogenation of 1,4,5,6-tetrahydropyrazine-2- (N-tert-butyl)carboxamide (2) was accomplished by a rhodium complex coordinated with a chiral diphosphine TRAP ligand, which is possible to chelate to a transition metal atom in a trans-manner. Of particular interest is that (R,R)-(S,S)-i-BuTRAP gave 97% ee of the corresponding piperazine-2- carboxylic acid derivative (3) with (S) configuration, while the hydrogenation with (R,R)-(S,S)-MeTRAP-rhodium catalyst provided (R)-3 with up to 85% ee. 31P NMR studies of behavior of i-Bu- and MeTRAP-rhodium catalysts during the reaction suggest that the asymmetric hydrogenation of 2 with TRAPs may involve two competitive reaction pathways, giving their respective enantiomeric products 3.
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U2 - 10.1021/jo981939u
DO - 10.1021/jo981939u
M3 - Article
AN - SCOPUS:0033582570
VL - 64
SP - 1232
EP - 1237
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 4
ER -