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1.	Chakka, Sai Kumar, et al. (author) Synthesis and Screening of C-1-Substituted Tetrahydroisoquinoline Derivatives for Asymmetric Transfer Hydrogenation Reactions 2010 In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :5, s. 972-980 Journal article (peer-reviewed)abstract Tetrahydroisoquinoline (TIQ) derivatives exhibit good biological activity. However, utilization of TIQ compounds in asymmetric catalysis is limited. This paper presents a series of TIQ derivatives in asymmetric transfer hydrogenation (ATH) reactions. Chiral TIQ amino alcohol ligands were synthesized and screened for the ATH reaction of aromatic ketones. The effect of a cis- and trans-phenyl substitution at the C-1 position on the ligand backbone was investigated both experimentally and computationally. The results showed that the trans orientation on the TIQ scaffold yields higher turnover rates with a selectivity of 94% ee obtained at room temperature with an Ru complex. The cis isomer results in a high turnover rate with no selectivity. The trans isomer gave 99% ee at lower temperatures. Furthermore, it was observed that substitution at the C-3-alpha position results in a drop of the enantioselectivity and the reactivity of the catalyst.

Chakka, Sai Kumar, et al. (author)
Synthesis and Screening of C-1-Substituted Tetrahydroisoquinoline Derivatives for Asymmetric Transfer Hydrogenation Reactions
2010
In: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :5, s. 972-980
Journal article (peer-reviewed)abstract
- Tetrahydroisoquinoline (TIQ) derivatives exhibit good biological activity. However, utilization of TIQ compounds in asymmetric catalysis is limited. This paper presents a series of TIQ derivatives in asymmetric transfer hydrogenation (ATH) reactions. Chiral TIQ amino alcohol ligands were synthesized and screened for the ATH reaction of aromatic ketones. The effect of a cis- and trans-phenyl substitution at the C-1 position on the ligand backbone was investigated both experimentally and computationally. The results showed that the trans orientation on the TIQ scaffold yields higher turnover rates with a selectivity of 94% ee obtained at room temperature with an Ru complex. The cis isomer results in a high turnover rate with no selectivity. The trans isomer gave 99% ee at lower temperatures. Furthermore, it was observed that substitution at the C-3-alpha position results in a drop of the enantioselectivity and the reactivity of the catalyst.

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