Mg-Promoted Regio- and Stereoselective C-Acylation of Aromatic α,β-Unsaturated Carbonyl Compounds

Abstract

[reaction: see text]. Treatment of aromatic alpha,beta-unsaturated carbonyl compounds with Mg turnings in the presence of acid anhydrides/TMSCl or acyl chlorides in DMF brought about a facile and efficient cross-coupling to give C-acylation products, which are useful 1,4-dicarbonyl compounds, in good to excellent yields in a regio- and stereoselective manner. The reaction may be initiated by electron transfer from magnesium to the substrates.

A Simple Protocol from Benzalacetones to 1,1,1‐Trifluoro‐2,5‐diketones and 2‐(Trifluoromethyl)furans by Reductive Trifluoroacetylation

“…As very versatile and readily available structural units, enones have been widely applied in many synthetic approaches . In our preceding research, we described magnesium‐promoted reductive coupling reactions of benzalacetone with acetyl chloride or acetic anhydride . In this study, as our strategy to construct the flamework of fluorinated 1,4‐diketones, reductive coupling of benzalacetone with ethyl trifluoroacetate was investigated.…”

Selective introduction of a trifluoroacetyl group onto 4-vinylpyridines through magnesium-promoted reduction

“…We have already reported numerous acylating reactions of electron-deficient carbons through umpolung by electron transfer 28,29 and recently clarified that ethyl trifluoroacetate would be a strong trifluoroacetylating agent at electron-deficient carbons in electron transfer reactions involving magnesium. 30e32 In this study, magnesium-promoted reductive coupling of 4-vinylpyridine (1a) and ethyl trifluoroacetate (2) in the presence of chlorotrimethylsilane in N-methyl-2-pyrrolidone (NMP) under mild conditions gave the corresponding trifluoroacetylated compound at the terminal olefinic carbon in good to excellent yields.…”

1,4-Bis(4-chlorophenyl)-2-hydroxybutane-1,4-dione

“…For the synthesis and applications of 1,4-dicarbonyl compounds, see: Ellison (1973); Hassner (1991); Ohno et al (2001). …”

“…For this reason, a number of methods for their synthesis have been developed and applied (Ellison, 1973;Ohno et al, 2001).…”