Investigations of the Scope and Mechanism of the Tandem Hydroesterification/Lactonization Reaction
作者:Lijun Wang、Paul E. Floreancig
DOI:10.1021/ol048378f
日期:2004.11.1
alcohols and 2-pyridylmethyl formate in the presence of Ru(3)(CO)(12) initiates a tandem sequence of hydroesterification and lactonization. Mechanistic studies suggest that regioselectivity and overall reaction efficiency are governed by the relative rates of reductive elimination and beta-hydride elimination for the alkylruthenium intermediates.
A high loading sulfonic acid-functionalized ordered nanoporous silica as an efficient and recyclable catalyst for chemoselective deprotection of tert-butyldimethylsilyl ethers
作者:Babak Karimi、Daryoush Zareyee
DOI:10.1016/j.tetlet.2005.04.100
日期:2005.7
A high loading sulfonic acid-functionalized ordered nanoporous silica efficiently catalyzes the deprotection of a variety of alcoholic TBDMS (tert-butyldimethylsilyl)ethers in methanol. The catalyst shows high thermal stability (up to 240 degrees C) and can be recovered and reused for at least seven reaction cycles without loss of reactivity. This method can be used to deprotect TBDMS ethers of alcohols in the presence of TBDMS ethers of phenols. (c) 2005 Elsevier Ltd. All rights reserved.
Oxidative cleavage of mono-, di-, and trisubstituted olefins to methyl esters through ozonolysis in methanolic sodium hydroxide
作者:James A. Marshall、Albert W. Garofalo
DOI:10.1021/jo00066a019
日期:1993.7
The ozonolysis of alkenes in methanolic NaOH or NaOMe with CH2Cl2 as cosolvent leads directly to methyl esters. The procedure has been used to prepare various alpha-, beta, and omega-alkoxy esters, acyloxy esters, and alpha- and beta-N-acyl and N-sulfonyl esters from the appropriate unsaturated ethers, esters, and amides. Other examples include the formation of dimethyl octanedioate from cyclooctene (75% yield), dimethyl nonanedioate and methyl nonanoate from methyl oleate (77 and 78%, respectively), and tetradecanoic acid gamma-lactone from 2-methyl-2-hexadecen-6-ol (80% yield).
EFFICIENT AND CHEMOSELECTIVE PROTECTION OF ALCOHOLS AND PHENOLS WITH <i>Tert</i>-BUTYLDIMETHYLCHLOROSILANE (TBDMCS) UNDER SOLVENT-FREE CONDITIONS
primary and secondary alcohols and phenols can be converted efficiently to their corresponding TBDMS ethers using TBDMCS/imidazole undersolvent-freeconditions. Elimination of DMF, accompanied with an easy non-aqueous work-up and a high rate enhancement of the reaction are worthy to be mentioned for the presented method. The reactions show absolute chemoselectivity for the protection of primary in the
Silica-coated Fe<sub>3</sub>O<sub>4</sub> magnetic nanoparticles-supported sulfonic acid as a highly active and reusable catalyst in chemoselective deprotection of tert-butyldimethylsilyl (TBDMS) ethers
employed in the deprotection of TBDMS ethers. The prepared magnetically separable nanocatalyst exhibited efficient catalytic activity with high conversion and selectivity in cleavage of TBDMS ethers. TBDMS ethers are efficiently cleaved to the corresponding hydroxyl compounds in methanol solution containing 2 mol% magnetic nano-catalysts. Good to excellent yields of products, simple work-up and product