Abstract
Described herein are differences in behavior between a Hantzsch ester and a benzothiazoline as hydrogen donors in the chiral phosphoric acid catalyzed asymmetric reductive amination of ketones with p-anisidine. The asymmetric reductive amination of ketones with a Hantzsch ester as a hydrogen donor provided the corresponding chiral amines exclusively, regardless of the structures of the ketones, whereas a similar transformation with a benzothiazoline provided chiral amines and p-methoxyphenyl-protected primary amines in variable yields, depending on the structures of both the ketones and benzothiazolines. Because a benzothiazoline has an N,S-acetal moiety that is vulnerable to p-anisidine, the primary amine can be formed through transimination of the benzothiazoline with p-anisidine followed by reduction of the resulting aldimine with remaining benzothiazoline.
| Original language | English |
|---|---|
| Pages (from-to) | 274-279 |
| Number of pages | 6 |
| Journal | Chemistry - An Asian Journal |
| Volume | 11 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2016 Jan 20 |
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Keywords
- benzothiazolines
- chiral phosphoric acid catalysis
- enantioselective reductive amination
- Hantzsch ester
- organic hydrogen donor
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Remarkable Differences in Reactivity between Benzothiazoline and Hantzsch Ester as a Hydrogen Donor in Chiral Phosphoric Acid Catalyzed Asymmetric Reductive Amination of Ketones. / Kim, Kyung Hee; Akiyama, Takahiko; Cheon, Cheol-Hong.
In: Chemistry - An Asian Journal, Vol. 11, No. 2, 20.01.2016, p. 274-279.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Remarkable Differences in Reactivity between Benzothiazoline and Hantzsch Ester as a Hydrogen Donor in Chiral Phosphoric Acid Catalyzed Asymmetric Reductive Amination of Ketones
AU - Kim, Kyung Hee
AU - Akiyama, Takahiko
AU - Cheon, Cheol-Hong
PY - 2016/1/20
Y1 - 2016/1/20
N2 - Described herein are differences in behavior between a Hantzsch ester and a benzothiazoline as hydrogen donors in the chiral phosphoric acid catalyzed asymmetric reductive amination of ketones with p-anisidine. The asymmetric reductive amination of ketones with a Hantzsch ester as a hydrogen donor provided the corresponding chiral amines exclusively, regardless of the structures of the ketones, whereas a similar transformation with a benzothiazoline provided chiral amines and p-methoxyphenyl-protected primary amines in variable yields, depending on the structures of both the ketones and benzothiazolines. Because a benzothiazoline has an N,S-acetal moiety that is vulnerable to p-anisidine, the primary amine can be formed through transimination of the benzothiazoline with p-anisidine followed by reduction of the resulting aldimine with remaining benzothiazoline.
AB - Described herein are differences in behavior between a Hantzsch ester and a benzothiazoline as hydrogen donors in the chiral phosphoric acid catalyzed asymmetric reductive amination of ketones with p-anisidine. The asymmetric reductive amination of ketones with a Hantzsch ester as a hydrogen donor provided the corresponding chiral amines exclusively, regardless of the structures of the ketones, whereas a similar transformation with a benzothiazoline provided chiral amines and p-methoxyphenyl-protected primary amines in variable yields, depending on the structures of both the ketones and benzothiazolines. Because a benzothiazoline has an N,S-acetal moiety that is vulnerable to p-anisidine, the primary amine can be formed through transimination of the benzothiazoline with p-anisidine followed by reduction of the resulting aldimine with remaining benzothiazoline.
KW - benzothiazolines
KW - chiral phosphoric acid catalysis
KW - enantioselective reductive amination
KW - Hantzsch ester
KW - organic hydrogen donor
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U2 - 10.1002/asia.201501020
DO - 10.1002/asia.201501020
M3 - Article
VL - 11
SP - 274
EP - 279
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
SN - 1861-4728
IS - 2
ER -