Practical One-Step Synthesis of Koga's Chiral Bases
作者:Eric Curthbertson、Peter O'Brien、Timothy D. Towers
DOI:10.1055/s-2001-12768
日期:——
A simple, efficient and practical method for the preparation of Koga"s chiral bases is described. The method involves attack of an amine on a styrene oxide-derived aziridinium ion and has allowed the synthesis of novel diamines which cannot be prepared using Koga"s original route.
Stereoselective Reactions. 25. Enantioselective Deprotonation of Prochiral 4-Substituted Cyclohexanones by Chiral Chelated Lithium Amides
作者:Ryuichi Shirai、Daisaku Sato、Kazumasa Aoki、Masahide Tanaka、Hisashi Kawasaki、Kenji Koga
DOI:10.1016/s0040-4020(97)00288-3
日期:1997.4
4-substituted cyclohexanones (4a∼d) by chiral chelated lithium amides (8a≈k) in the presence of excess trimethylsilyl chloride was realized to give the corresponding chiral silyl enol ethers (6a∼d) in up to 89% ee. It is shown that enantioselectivity of the reaction is dependent on the solvent used, but becomes almost independent on the solvent in the presence of HMPA. The sense of asymmetric induction
The invention relates to compounds of formula (I)
Z-C(R
1
R
2
)—C(R
3
NH
2
)—C(R
4
R
5
)—X—N(R
6
R
7
) (I),
wherein Z, R
1-7
and X have the meaning as cited in the description and the claims. Said compounds are useful as DPP-IV inhibitors. The invention also relates to the preparation of such compounds as well as the production and use thereof as medicament.