Base-catalyzed condensation of acetophenone and isobutyraldehyde. Reexamination of the monomeric and dimeric adducts

Abstract

vel. 15 The isoheptyl bromide16 was obtained in 90% yield and distilled at 84-85°(45 mm) [lit.14 83°(45 mm)].The Grignard reagent from 1 mol of isoheptyl bromide was prepared and treated with allyl bromide according to the directions of Vogel.17 The product, 8-methyl-1-nonene, was distilled in a tenplate column at 170-171°. No impurities could be detected in the product by glpc analysis.

A green synthesis of highly substituted 1,5-diketones

“…(3) Better yields and diastereoselectivities were obtained than those for most reported procedures. [21][22][23] Only Novikov and Tishchenko reported a yield higher than 90%. 24 All other reports had yields around 60%.…”

“…(1) Water was used as reaction media instead of MeOH. [21][22][23][24] (2) The aqueous KOH was recyclable.…”

“…24 All other reports had yields around 60%. [21][22][23] (4) The product workup was very simple. As the solid product formed during the reaction, it all adhered together as one large clump of material (ESI, S2, Picture 2 †).…”

“…Dimerization of the condensation products between aryl methyl ketones and aldehydes under basic conditions can also produce 1,5-diketones. [21][22][23][24] However, all the current methods employ volatile and toxic organic solvents such as methanol, which violates the principles of "green chemistry". [25][26][27] Several groups including ours have reported the successful replacement of volatile organic solvents with water for various organic synthetic reactions.…”

“…The reaction produces better yields and diastereoselectivities, has a simpler workup and is more energy efficient than previously reported organic-solvent mediated reactions. [21][22][23][24]…”