Synthesis of derivatives of prenylacetic acids by reactions of alkyl malonate, cyanoacetate, and acetoacetate with alkylating reagents in ionic liquids
作者:G. V. Kryshtal、G. M. Zhdankina、S. G. Zlotin
DOI:10.1023/b:rucb.0000035652.61455.b9
日期:2004.3
A method for the synthesis of carboxylic acid derivatives containingone or two —CH2CHn(Me)CHn+1CH2— fragments (n = 0, 1) was developed. The method is based on the alkylation of (di)alkyl malonates, cyanoacetates, and acetoacetates with acyclic prenyl halides in ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate and tetrafluoroborate. For the ambident ethyl acetoacetate anion, the reactions
Highly Stereoselective Palladium(0)-Catalyzed Allylation of Active Methylene Compounds with Allyl Imidates under Neutral Conditions
作者:Osamu Suzuki、Seiichi Inoue、Kikumasa Sato
DOI:10.1246/bcsj.62.239
日期:1989.1
In the presence of a catalytic amount of Pd(0), active methylene compounds were allylated by allyl imidates under neutral conditions. In allylation with 3,3-disubstituted allyl imidates, e.g., geranyl and neryl imidate the effect of solvent and ligand to the E/Z ratio are investigated. The reaction in dimethyl sulfoxide by addition of diphosphine, e.g., 1,2-bis(diphenylphosphino)ethane, or large excess
Reactions of CH-acids with , -unsaturated aldehydes in ionic liquids
作者:G. V. Kryshtal、G. M. Zhdankina、I. V. Astakhova、S. G. Zlotin
DOI:10.1023/b:rucb.0000035651.60150.53
日期:2004.3
carbonate-catalyzed reactions of CH-acids (diethyl malonate, ethyl acetoacetate, ethyl cyanoacetate, and ethyl 2-acetyl- and 2-ethoxycarbonyl-5,9-dimethyldeca-4,8-dienoates) with α,β-unsaturated aldehydes (acrolein, crotonaldehyde, citral) were studied in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6], and in a 1-butyl-3-methylimidazolium bromide ([bmim][Br]) — benzene system. The reactions
Preparation of the Geranyl-α-pyrone (±)-Aurantiacone via a New Pyrone Synthesis
作者:Uwe Beifuss、Dietmar Schmidt、Jürgen Conrad、Iris Klaiber、Sabine Mika
DOI:10.1055/s-2007-967996
日期:2007.2
The structure of the leaf resin geranyl-α-pyrone aurantiacone isolated from Mimulus ( = Diplacus) aurantiacus (Curtis) Jeps. (Scrophulariaceae) was confirmed through synthesis. The key step is lactonization of the sensitive 5-hydroxy-3-oxopent-4-enoic acid under mild conditions, which can be released from the corresponding bispotassium salt. The latter is accessible in a few steps from an N-acyl aziridine and an ethyl acetoacetate.
Organic Photocatalytic Cyclization of Polyenes: A Visible-Light-Mediated Radical Cascade Approach
作者:Zhongbo Yang、Han Li、Long Zhang、Ming-Tian Zhang、Jin-Pei Cheng、Sanzhong Luo
DOI:10.1002/chem.201503118
日期:2015.10.12
A visible‐light‐mediated, organic photocatalytic stereoselective radical cascade cyclization of polyprenoids is described. The desired cascade cyclization products are achieved in good yields and high stereoselectivities with eosin Y as photocatalyst in hexafluoro‐2‐propanol. The catalyst system is also suitable for 1,3‐dicarbonyl compounds, which require only catalytic amounts of LiBr to promote the