Asymmetric transfer hydrogenation of cyclic imines in water with a versatile hydrogen donorformic acid/N-methylpiperidine: rapid access to highly enantioselective amines
|Title||Asymmetric transfer hydrogenation of cyclic imines in water with a versatile hydrogen donorformic acid/N-methylpiperidine: rapid access to highly enantioselective amines|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Shende, VS, Shingote, SK, Deshpande, SH, Kelkar, AA|
Asymmetric transfer hydrogenation (ATH) of cyclic imines in water has been investigated for the first time by using HCOOH in combination with bases other than triethylamine as H donor. Effect of FA/Base ratio has shown significant impact on activity and enantioselectivity for ATH reaction in water. Use of methanol as a co-solvent improved the reduction performance. FA/N-methylpiperidine was found to be excellent, versatile hydrogen donor for ATH of imine 6,7-dimethoxy-1-methyl-3,4-dihy-droisoquinoline (1a) giving by far the highest noted TOF value of 5940 h(-1). ATH of-different imines derivatives including 3, 4-dihydoisoquinolines, beta-carbolines and cyclic sulfonyl imines have been performed with excellent activity (91-99% yield) and enantioselectivity (88-97%) in very short time (1-2 min). This is very simple protocol for rapid access to enantioselective amines with very new and versatile hydrogen donor 1.1 FA/Nmethylpiperidine.
|Type of Journal (Indian or Foreign)|| |
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