A modular approach for ligand design for asymmetric allylic alkylations via enantioselective palladium-catalyzed ionizations
摘要:
A new class of ligands for asymmetric transition metal catalysis based on 2-(diphenylphosphino)benzoic acid was used in a mechanistically-defined palladium-catalyzed reaction in which enantiodifferentiation was the result of selective ionization of substrates derived from cis-2-cycloalkene-1,4-diols. By making rational, stepwise changes in the ligand structure, the structural requirements for good asymmetric induction were probed. The absolute stereochemistry of the products was found to be related to the chirality of the ligand in a predictable fashion. A mnemonic is given which allows one to predict the mode of ionization (R or S) solely on the basis of the stereochemistry of the variable chiral linker used to make the ligand.
Total synthesis of Δ12-PGJ2, 15-deoxy-Δ12,14-PGJ2, and related compounds
作者:Hukum P. Acharya、Yuichi Kobayashi
DOI:10.1016/j.tetlet.2003.11.143
日期:2004.2
α′-position with the ω-chain aldehydes followed by dehydration to produce the title compounds. In a similar manner, 5-dehydro compounds (acetylene analogues) were synthesized successfully. In addition, palladium-catalyzed reaction of 4-cyclopentene-1,3-diol monoacetate with methyl malonate, the first step of the synthesis, was improved to afford the product in high yield by using t-BuOK or LDA in place
Enantioselective Synthesis of Both Enantiomers of Dimethyl<i>cis</i>-(4-Acetoxycyclopent-2-enyl)malonate, Key Intermediates for Epijasmonate
作者:Shinji TANIMORI、Yuko TSUJI、Mitsunori KIRIHATA
DOI:10.1271/bbb.66.660
日期:2002.1
Bothenantiomers (3 and 4) of dimethyl cis-(4-acetoxycyclopent-2-enyl)malonate (3), known intermediates for the synthesis of epijasmonate, were prepared in an enantio-enriched form from common starting material 2 based on desymmetrization of the meso-character by palladium-catalyzed asymmetric allylic alkylation.
Methyl-jasmonat: Ein kurzer Weg zum Naturstoff und seinem unnatürlichen Enantiomer<i>via</i>Palladium(0)-induzierte, enantiodivergente Alkylierung von Cyclopent-2-en-1,3-diol-Derivaten
Methyl Jasmonate: A Short Synthesis of Naturally Occurring Methyl Jasmonate and its Unnatural Enantiomer via Enantiodivergent Alkylation of Cyclopent-2-ene-1,3-diol Derivatives by Palladium(0)-Induced Reactions
Strategy for synthesis of the isoleucine conjugate of epi-jasmonic acid
作者:Narihito Ogawa、Yuichi Kobayashi
DOI:10.1016/j.tetlet.2008.09.144
日期:2008.12
The TES ether of 2-((1R,2S,3R)-3-hydroxy-2-((Z)-pent-2-enyl)cyclopentyl)acetic acid (5, equal to the reduction product of epi-jasmonic acid) derived from (1R,4S)-4-hydroxycyclopent-2-enyl acetate (19) in 13 steps was activated by using isobutyl chloroformate and was subjected to condensation with isoleucine at room temperature for 48 h. The product was desilylated and oxidized to the isoleucine conjugate of epi-jasmonic acid in 68% yield over three steps. Similarly, allo-isoleucine conjugate of epi-jasmonic acid and three isoleucine conjugates of ent-epi-jasmonic acid, jasmonic acid, and ent-jasmonic acid were synthesized. (C) 2008 Elsevier Ltd. All rights reserved.
Enantioselective preparation of functionalized cyclopentanoids via a common chiral (.pi.-allyl)palladium complex
作者:Donald R. Deardorff、Robert G. Linde、Amanda M. Martin、Michael J. Shulman