A Sulfone-Based Strategy for the Preparation of 2,4-Disubstituted Furan Derivatives
作者:Nathan R. Haines、Aaron N. VanZanten、Anthony A. Cuneo、John R. Miller、William J. Andrews、David A. Carlson、Ryan M. Harrington、Adam M. Kiefer、Jeremy D. Mason、Julie A. Pigza、S. Shaun Murphree
DOI:10.1021/jo201529s
日期:2011.10.7
3-dibromo-1-phenylsulfonyl-1-propene (DBP, 2) with 1,3-diketones under basic conditions. The furan-forming step involves a deacetylation, and the selectivity of this process depends upon the steric demand of the R group. The substituent in position 4 is elaborated by reaction of sulfonyl carbanions with alkyl halides, acyl halides, and aldehydes. Oxidative or reductive desulfonylation produces the 2,4-disubstituted
α-Diazo-β-ketonitriles: Uniquely Reactive Substrates for Arene and Alkene Cyclopropanation
作者:Roger R. Nani、Sarah E. Reisman
DOI:10.1021/ja401610p
日期:2013.5.15
An investigation of the intramolecular cyclopropanation reactions of alpha-diazo-beta-ketonitriles is reported. These studies reveal that alpha-diazo-beta-ketonitriles exhibit unique reactivity in their ability to undergo arene cyclopropanation reactions; other similar acceptor acceptor-substituted diazo substrates instead produce mixtures of C-H insertion and dimerization products. alpha-Diazo-beta-ketonitriles also undergo highly efficient intramolecular cyclopropanation of tri- and tetrasubstituted alkenes. In addition, the alpha-cyano-alpha-ketocyclopropane products are demonstrated to serve as substrates for S(N)2, S(N)2', and aldehyde cycloaddition reactions.
The Krapcho decarboxylation of alkyl malonate derivatives has been adapted to aqueous microwave conditions. Various salt additives were examined, and both the cation and the anion impacted the facility of the reaction. A strong correlation was found between the pKa of the anion and the reaction rate, suggesting a straightforward base-catalyzed hydrolysis. Lithium sulfate gave the best results, obviating the need for DMSO co-solvent.
Mild Conversion of β-Diketones and β-Ketoesters to Carboxylic Acids
作者:Yang Zhang、Jingliang Jiao、Robert A. Flowers
DOI:10.1021/jo0602975
日期:2006.6.1
A mild protocol for the conversion of β-ketoesters and β-diketones to carboxylic acids with use of CAN in CH3CN is described. The method is compatible with a number of functional groups, and can generate carboxylic acids under neutral conditions at room temperature. The reaction is fast and general, providing an alternative method to the commonly used malonicester acid preparation. Initial mechanistic
A New, Simple, and General Synthesis of 1,3-, 1,4- and 1,5-Diketones from Functionalized Nitroalkanes
作者:Roberto Ballini、Giuseppe Bartoli
DOI:10.1055/s-1993-25981
日期:——
Herein is reported the utilization of protected nitro ketones, in the synthesis of 1,3-, 1,4-, and 1,5-diketones, by their condensation with aldehydes then conversion of the obtained conjugated nitroalkenes into monoprotected carbonyl derivatives which, by removal of the protecting group, gives diketones.