Abstract
The detailed synthesis and characterization of (-)-11-(triethoxysilyl)-10,11-dihydrocinchonidine (4), a starting material for the immobilization of (-)- cinchonidine on silica based supports, is described. Compound 4 together with its precursors 9-O-(trimethylsilyl)cinchonidine (2) and 9-O-(trimethylsilyl)-11-(triethoxysilyl)-10,11-dihydrocinchonidine (3) were employed as chiral modifiers in the hydrogenation of a prochiral diketone, 1-phenylpropane-1,2-dione, over a heterogeneous Pt/Al2O3 catalyst using cinchonidine (1) as a reference modifier. The unexpected enhancement of ee induced by 4, demonstrating the positive effect of distal modifier substitution, is discussed in the light of molecular modeling and NMR studies.
Original language | Undefined/Unknown |
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Pages (from-to) | 2605–2612 |
Number of pages | 8 |
Journal | Journal of the Chemical Society, Perkin Transactions 1 |
Issue number | 23 |
DOIs | |
Publication status | Published - 2002 |
MoE publication type | A1 Journal article-refereed |