Methyl α-d-glucopyranoside based monoaza-15-crown-5 type lariat ethers with different heteroatom-containing side arm attached to the nitrogen of the macrocyclic ring have been synthesized. These compounds were used as chiral phase transfer catalysts in a few asymmetric reactions, such as Michael additions, Darzens condensation, and epoxidation of chalcone. The side arms of the macrocycles had a significant
A new, efficient crown ether 1 anellated to a sugar derivative has been prepared which shows significant asymmetric induction as phase transfer catalyst in the Michael addition of 2-nitropropane to chalcone (60% ee for the S antipode) and in the Darzens condensation of phenacyl chloride and benzaldehyde (64% ee), simultaneously changing the PT process from solid-liquid to liquid-liquid phase.
New chiral monoaza-15-crown-5 derivatives and lariat ethers anellated to phenyl β-D-glucoside have been synthesized which show significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (84% ee) and in the Darzens condensation of phenacyl chloride with benzaldehyde (74% ee).
Synthesis, extraction ability and application in asymmetric synthesis of azacrown ethers derived from D-glucose
作者:Péter Bakó、Kristóf Vízvárdi、Suzanne Toppet、Erik Van der Eycken、Georges J. Hoornaert、László Tõke
DOI:10.1016/s0040-4020(98)00938-7
日期:1998.12
A number of new chiral monoaza-15-crown-5 derivatives (4–9) and lariat ethers (10–15) anellated to phenyl-β-D-glucopyranoside have been synthesized. Their extracting ability was measured with alkali metal (Li, Na, K) and ammonium cations. The derivatives show significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (82% ee) although in low yield
induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (87% ee), in the Darzenscondensation of phenacyl chloride with benzaldehyde (71% ee) and in the self-condensation of phenacyl chloride (64% ee) to give 14. The absolute configurations of (−)-(2R,3S)-epoxy-3-(4-chlorophenyl)-1-phenyl-1-propanone 12 and (−)-4-chloro-(2R,3S)-epoxy-1,3-diphenyl-1-butanone 14 have