Facile and Selective Cleavageof Allyl Ethers Based on Palladium(0)-Catalyzed Allylic Alkylationof<i>N</i>,<i>N</i>′-DimethylbarbituricAcid
作者:Hirokazu Tsukamoto、Yoshinori Kondo
DOI:10.1055/s-2003-39320
日期:——
The classical palladium(0)-catalyzed allylic alkylation of N,N'-dimethylbarbituric acid can be applied to the facile and selective cleavage of allylic alkyl ethers to release the corresponding alcohols in excellent yield.This reaction proceeds under neutral conditions without any additive to activate the allyl ethers and tolerates various functional groups, such as ester, ether, ketone, alkyl and aryl
Remarkable Solvent Effect on Pd(0)-Catalyzed Deprotection of Allyl Ethers Using Barbituric Acid Derivatives: Application to Selective and Successive Removal of Allyl, Methallyl, and Prenyl Ethers
Pd(0)-catalyzed deprotection of allylethers using barbituric acid derivatives in protic polar solvent such as MeOH and aqueous 1,4-dioxane proceeds at room temperature without affecting a wide variety of functional groups. Control of the reaction temperature allows selective and successive cleavage of allyl, methallyl, and prenyl ethers. A study of ligand effects on the deprotection reveals that the
A mild and efficient selective tetrahydropyranylation of primary alcohols and deprotection of THP ethers of phenols and alcohols using PdCl2(CH3CN)2 as catalyst
作者:Yan-Guang Wang、Xiao-Xing Wu、Zhi-Yong Jiang
DOI:10.1016/j.tetlet.2004.02.057
日期:2004.3
Primary alcohols were selectively tetrahydropyranylated in good to excellent yields at room temperature using PdCl2(CH3CN)2 as catalyst in tetrahydrofuran (THF) in the presence of phenols, secondary, and tertiary alcohols. The tetrahydropyranyl (THP) group could be efficiently removed using PdCl2(CH3CN)2 as catalyst in CH3CN, while other protection groups such as p-toluenesulfonyl (Ts), tert-butyldiphenylsilyl
Child's play! Allyl ethers as protecting groups for hydroxyl functions can be removed readily with a combination of DIBAL and catalytic amounts of [NiCl2 (dppp)]. Propene is expelled in this remarkably selective reaction, and a nickel-catalyzed hydroalumination-elimination pathway is proposed [Eq. (a)]. dppp=propane-1,3-diylbis(diphenylphosphane).
Deprotection of Tetrahydropyranyl Ethers with Montmorillonite K-10 Clay in Methanol
作者:Takahiko Taniguchi、Kohei Kadota、Adel S. ElAzab、Kunio Ogasawara