Reductive acylation magnesium

Reductive acylation. Treatment of anthracene and a dicarboxylic acid chloride with magnesium in DMF leads to the dibenzo bridged diketone product. ... 

Acylation. Acylation is the most rehable means of introducing a 3-substituent on the indole ring. Because 3-acyl substituents can be easily reduced to 3-aLkyl groups, a two-step acylation—reduction sequence is often an attractive alternative to direct 3-aLkylation. Several kinds of conditions have been employed for acylation. Very reactive acyl haUdes, such as oxalyl chloride, can effect substitution directiy without any catalyst. Normal acid chlorides are usually allowed to react with the magnesium (15) or 2inc (16) salts. The Vilsmeier-Haack conditions involving an amide and phosphoms oxychloride, in which a chloroiminium ion is the active electrophile, frequentiy give excellent yields of 3-acylindoles. 

Picard has reported more direct approaches to acyl silanes and to their silyl enol ethers by reductive silylation of substituted benzoates and of w./i-dihalo-a, /Tunsaturated acyl chlorides, respectively, using a similar reagent mixture of trimethylchlorosilane, magnesium and IIMPA96. 

The reaction of 2-acetylphenothiazine with ethyl magnesium bromide led to 2-(but-2-enyl)phenothiazine (156) A-substituted ketones gave ethynyl derivatives (157) on treatment with acetylene. Reduction of 2-acyl derivatives to alcohols has been performed by the Meerwein-Ponndorf reaction and by using LiAlH. - - Polarographic one-electron reduction of the keto group in 10-acetyl-2-()3-piperidinopropionyl)phenothiazine has been reported. ... 

Trimethylsilylmethyl Af-methylanilides (20.1) are conveniently synthesized from a nitrobenzene by successive treatments with trimethylsilyimethyl magnesium chloride at 0°C, reduction of the nitro group and yV-acylation. The anilide cyclizes in high yield at — 20°C. 

The addition of asymmetric a-alkoxy-carbanions (31) to aldehydes has been shown to lead preferentially to 5 j /i l,2-diols (Scheme 21) the Jjiw-selectivity is increased when the a>oxygen function is protected as an acetal (e,g. R == CHgOCHgPh) and when magnesium rather than lithium derivatives are employed. Acylation-reduction of (31) affords the corresponding on i-diols (also Scheme 21). ... 

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