Convenient, High-Yield Method for the Methylation of 1,3-Diketones
作者:Anil Choudhary、Alfons L. Baumstark
DOI:10.1055/s-1989-27359
日期:——
A general method for the facile dimethylation of 1,3-diketones is presented. The method involves the use of readily available, inexpensive reagents and is carried out under mild conditions. Monomethylation may be carried out by slight modification (simplification) of the procedure. Several examples are presented which show that the method is applicable to alkylations with primary halides as well. Isolated yields for monoalkylation are approximately 95% while those for dialkylation are â90%. Alkylation is taking place by the reaction of the enolates of 1,3-diketones [generated in toluene by treatment with anhydrous potassium carbonate in the presence of tetraalkylammonium bromide (phase-transfer catalyst)] with alkyl halides.
An iridium-catalyzed coupling reaction of alcohols with enones has been successfully developed providing access to 1,3-diketones with high selectivity in good yields. This reaction provides an atom-economical route to 1,3-diketones from readily available alcohols.
Photo-mediated [1, 3]-Carbonyl shift of β-Ketocarbonyls
作者:Wenzhao Zhang、Yao Li、Sanzhong Luo
DOI:10.1016/j.jphotochem.2020.112553
日期:2020.6
An organic amine mediated photolytic [1,3]-benzoyl migration of β-benzoyl carbonylcompounds was reported. This migration was achieved by Norrish-Yang cyclization and retro-aldol reaction under black light (365 nm) or visible light irradiation. This photolytic protocol provides an alternative approach to the synthesis of 1,5-dicarbonyl compounds. By chiral primary amine catalysis, a kinetic resolution
Stereoselective Synthesis of α-Ylidene-β-dicarbonyl Compounds: A Mild PhI(OAc)<sub>2</sub>-mediated Dehydrogenation Process
作者:Liyan Fan、Wen Chen、Kunshan Tang、Dongbei Wu
DOI:10.1246/cl.2012.940
日期:2012.9.5
PhI(OAc)2-mediated dehydrogenation of α-alkyl-β-dicarbonyl compound has been developed to afford α-ylidene-β-dicarbonyl compounds with high stereoselectivity under mild conditions. This process provides a complementary entry to stereoselectivity for the Knoevenagel reaction.
Coating compositions having extented pot life and short cure time
申请人:ROHM AND HAAS COMPANY
公开号:EP0882748A2
公开(公告)日:1998-12-09
A combination of chemicals suitable for extending pot life and shortening cure time of a pot mix of a thermosetting composition is disclosed. The combination of chemicals includes a catalyst, such as, dibutyl tin dilaurate; carboxylic or sulfonic acid; and an extender compound, such as 2,4 pentanedione. The combination is generally included in a polymeric component of the urethane composition. The extended pot life provides the user with longer open time during which to efficiently apply a coating of the pot mix over a wide variety of substrate surfaces while still producing coatings that cure quickly upon application.