Tert-Butyl acetyl chloride

Acetyl chloride, a-tert butyl-o-cyano- [Butyryl chloride, 2-cyano-3 3-dimethyl-], 55,38... 

All reactants should be pure and anhydrous. The tert.-butyl alcohol should be dried over quicklime and the dimethylani-line redistilled. Reagent grade acetyl chloride should be employed. 

The preparation of enantiomerically pure chemicals is also the theme of the next group of four procedures. The biopolymer polyhydroxybutyric acid, which is now produced on an industrial scale, serves as the starting material for the large scale synthesis of (R)-3-HYDROXYBUTANOIC ACID and (R)-METHYL 3-HYDROXYBUTANOATE. Esters of (-)-camphanic acid are useful derivatives for resolving and determining the enantiomeric purity of primary and secondary alcohols. An optimized preparation of (-)-(1S,4R)-CAMPHANOYL CHLORIDE is provided. The preparation of enantiomerically pure a-hydroxyketones from ethyl lactate is illustrated in the synthesis of (3HS)-[(tert)-BUTYL-DIPHENYLSILYL)OXY]-2-BUTANONE. One use of this chiral a-hydroxyketone is provided in the synthesis of (2S,3S)-3-ACETYL-8-... 

The original Garner preparation3 of 5 involves the conversion of serine into the protected methyl ester 3 and controlled reduction of the latter by DIBAL. The reaction sequence employed for the preparation of 3 involves the protection of the amino acid as N-Boc derivative using di-tert-butyl dicarbonate, esterification with methyl iodide or diazomethane, and acetonization with 2,2-dimethoxypropane under acid catalysis. The N-Boc methyl serinate and the ester 3 require purification by vacuum distillation or chromatography. In a modification to this procedure reported by McKillop,2 the esterification reaction of serine is carried out first by methanol/acetyl chloride. The resulting ester is then converted into the N-Boc derivative 2 with di-tert-butyl dicarbonate and the latter transformed into 3 by acetonization. This procedure avoids... 

In a i-l. round-bottomed flask are placed 12 g. (0.5 gram atom) of magnesium powder, 37 g. (0.5 mole) of tert.-butyl alcohol, and 100 g. of anhydrous ether (Note 1). The flask is fitted with an addition tube, one arm of which bears a reflux condenser, and the other arm a dropping funnel. While the mixture is being shaken by hand, a solution of 55 g. (0.7 mole) of acetyl chloride (Note 2) in 50 g. of anhydrous ether is added dropwise (Note 3). A lively reaction gradually ensues with evolution of hydrogen, mixed with ether vapor and a little hydrogen chloride (Note 4). After all the acetyl chloride has been added, the reaction mixture is allowed to stand in a pan of cold water for one hour (Note 5). After another hour at room temperature the mixture is warmed in a water bath at 40-45° for one-half hour in order to complete the reaction. 

Et2AlCl could be replaced by the sesquichloride or by a mixture of a trialkylaluminum and a reactive halide such as benzyl chloride or tert-butyl chloride. The effective cobalt compounds were those which are known to yield cis-1,4-polybutadiene—e.g. cobalt stearate, cobalt acetyl-acetonate, cobalt bis(salicylaldehyde imine), cobalt chloride-pyridine, etc. Et2AlCl concentration could be varied within the range 0.3-5% by weight based on PVC, and the cobalt compound concentration was 0.002-0.01 mole per mole of Et2AlCl. 

Easily dissociable, highly polar organic compounds were used occasionally as cationic initiators. Thus, triphenyl methyl chloride (77), triphenyl methyl chloromercurate (72), alkyl, acyl, and nitronium tetra-fluoro borates (13), silver perchlorate (77, 14), lithium perchlorate (75), acetyl, benzoyl, and tert.-butyl perchlorate (16) and acetyl fluoroborate (16) were mentioned at various times as catalysts for cationically initiable monomers. 

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