Organocatalyzed Michael–Henry reactions: enantioselective synthesis of cyclopentanecarbaldehydes via the dienamine organocatalysis of a succinaldehyde surrogate
Anodic Oxidation of Unsaturated Aliphatic Ethers in aqueous electrolytes
摘要:
2,5-dihydrofuran 1 was galvanostatically oxidized in aqueous electrolytes on Pt and PbO2 anodes at current densities of 10 to 50 mA cm(-2). Under acidic conditions maleic dialdehyde 2 was obtained on bath electrodes with a current efficiency (c.e.) of up to 50%. In the alkaline region (pH 10) 4-hydroxy crotonic aldehyde 3 (Pt) or 2,5-dihydrofuranone 4 (PbO2) become the main products with c.e.'s of 29% and 27%, respectively, depending on the anode material. The influence of pH and of the anode material are discussed in detail. 2,3-dihydrofuran 7, vinyl ethyl ether 8 and for comparison, furan 9 were studied in addition.
Structural Definition of Early Lysine and Histidine Adduction Chemistry of 4-Hydroxynonenal
作者:Durgesh V. Nadkarni、Lawrence M. Sayre
DOI:10.1021/tx00044a014
日期:1995.3
could confirm unambiguously the structure of a HNE-His imidazole(N tau) Michael adduct, stabilized as a cyclic hemiacetal and isolated from a neutral aqueous 1:1 stoichiometry reaction mixture. In the case of Lys/amine reactivity, where an excess of amine is needed to avert HNE aldol condensation, the predominance of a 1:1 Michael adduct in homogeneous aqueous solution and a 1:2 Michael-Schiff base
N-Heterocyclic Carbene Catalyzed Generation and [4+2] Annulation of Unsubstituted Dienolate - Enantioselective Synthesis of Spirocyclic Oxindolodihydropyranones
作者:Jin-Tang Cheng、Xiang-Yu Chen、Zhong-Hua Gao、Song Ye
DOI:10.1002/ejoc.201403395
日期:2015.2
The N-heterocycliccarbenecatalyzed (NHC-catalyzed) generation of unsubstituted dienolate (butadienolate) and subsequent [4+2] annulation reactions with isatins afford chiral spirocyclic oxindolodihydropyranones in moderate to good yields with moderate to good enantioselectivities.
Asymmetric Michael addition of boronic acids to a γ-hydroxy-α,β-unsaturated aldehyde catalyzed by resin-supported peptide
作者:Kengo Akagawa、Masahide Sugiyama、Kazuaki Kudo
DOI:10.1039/c2ob25431j
日期:——
A resin-supportedpeptidecatalyst effective for the asymmetric Michael addition of boronic acids to (E)-4-hydroxybut-2-enal was developed. From a spectral study, it was revealed that the optimum peptide consisted of both a β-turn and helix. Such a combination of secondary structures was essential for achieving a high catalytic ability.
Organocatalytic asymmetric 1,4-addition of organoboronic acids to γ-hydroxy α,β-unsaturated aldehyde: facile synthesis of chiral β-substituted γ-lactones
作者:Sung-Gon Kim
DOI:10.1016/j.tetlet.2008.08.025
日期:2008.10
Catalytic asymmetric 1,4-addition of arylvinyl- and arylboronic acids to a γ-hydroxy α,β-unsaturatedaldehyde, which affords β-substituted γ-lactols, has been established using a diarylprolinol silyl ether as an organocatalyst. The β-substituted γ-lactols have been obtained in good yields and with up to 91% ee, which lead to chiral β-substituted γ-lactones followed by oxidation.