Neopentyl alcohol, reaction with

Amination. Amyl alcohols can react with ammonia or alkylamines to form primary, secondary, or tertiary-substituted amines. Eor example, 3-methyl-butylamine [107-85-7] is produced by reductive ammonolysis of 3-methyl-1-butanol over a Ni catalyst at 150°C (59). Some diisoamyl- and triisoamyl amines are also formed in this reaction. Good selectivities (88%) of neopentyl amine [5813-64-9] are similarly produced by reductive ammonolysis of neopentyl alcohol (60). 

Other Reactions. Primary amyl alcohols can be halogenated to the corresponding chlorides by reaction with hydrogen chloride in hexamethylphosphoramide (87). Neopentyl chloride [753-89-9] is formed without contamination by rearrangement products. A convenient method for preparing / f/-amyl bromide and iodide involves reaction of / f/-amyl alcohol with hydrobromic or hydroiodic acid in the presence of Li or Ca haUde (88). The metal haUdes increase the yields (85 —95%) and product purity. 

These reactions are also quite sensitive to steric factors, as shown by the fact that if 1-butene reacts with di(j iAisoamyl)borane the initially formed product is 99% substituted in the 1-position (15) compared to 93% for unsubstituted borane. Similarly, the product obtained from hydroformylation of isobutylene is about 97% isoamyl alcohol and 3% neopentyl alcohol (17). Reaction of isobutylene with aluminum hydride yields only triisobutjlaluininum. 

Further optimization of this reaction was carried out with TFE as an achiral adduct, since reaction with TFE is much faster than that with neopentyl alcohol. We found that dimethyl- and diethylzinc were equally effective, and the chiral zinc reagent could be prepared by mixing the chiral modifier, the achiral alcohol and dialkylzinc reagent in any order without affecting the conversion and selectivity of the reaction. However, the ratio of chiral to achiral modifier does affect the efficiency of the reaction. Less than 1 equiv of the chiral modifier lowered the ee %. For example with 0.8 equiv of 46 the enantiomeric excess of 53 was only 58.8% but with 1 equiv of 46 it was increased to 95.6%. Reaction temperature has a little effect on the enantiomeric excess. Reactions with zinc alkoxide derived for 46 and TFE gave 53 with 99.2% ee at 0°C and 94.0% ee at 40°C. 

Reaction of tris(neopentyl) complexes of titanium, zirconium and hafnium with molecular oxygen furnishes the corresponding tris(neopentoxy) complexes [42, 43, 51]. A peroxo complex is an intermediate in this reaction, being relatively stable in the case of titanium [42]. The alkoxide species can also be formed upon reaction with alcohols under mild conditions [42, 52]. The alcoholysis reaction is fast, with a low dependence on the steric hindrance of the alkyl chain [42]. Hydrolysis leads to ](=SiO)M(OH)3] or ](=SiO)2M(OH)2], depending on the precursor species. Deu-... 

High yields (76-81%) of alcohols are also obtained by adding solutions of acyl chlorides in anhydrous dioxane or diethyl carbitol to a suspension of sodium borohydride in dioxane and brief heating of the mixtures on the steam bath [751], by stirring solutions of acyl chlorides in ether for 2-4 hours at room temperature with aluminum oxide (activity I) impregnated with a 50% aqueous solution of sodium borohydride (Alox) (yields 80-90%) [1014], by refluxing acyl chlorides with ether solutions of sodium trimethoxyborohydride [99], or by treatment of acyl chlorides in dichloromethane solutions with tetrabutylammonium borohydride at —78° [771]. A 94% yield of neopentyl alcohol was achieved by the reaction of trimethylacetyl chloride with tert-butylmagnesium chloride [324]. 

Alkyl sulfates, tosylates, and other esters of sulfuric and sulfonic acids can be converted to alkyl halides with any of the four halide ions.979 Neopentyl tosylate reacts with Cl, Br, or I without rearrangement in HMPA.980 Similarly, allylic tosylates can be converted to chlorides without allylic rearrangement by reaction with LiCl in the same solvent.981 Inorganic esters are intermediates in the conversion of alcohols to alkyl halides with SOCl2, PC15, PC13, etc. (0-67), but are seldom isolated. 

The nucleophilic displacement of halogens by fluorine can be successfully carried out by reaction with potassium fluoride under several conditions. Primary and secondary alkyl halides 1 are converted to the corresponding fluorides 2 by heating with a saturated aqueous solution of potassium fluoride in the presence of catalytic amounts of hexadecyltributylphosphonium bromide.56 Small amounts of the corresponding alcohol and the olefinic elimination product are formed as side products. While neopentyl bromide does not react at all, polyhaloalkanes give only products of elimination or hydrolysis. Chlorocyclohexane gives only the elimination product.56... 

Til contrast, the reaction in basic alcoholic solution with Na+OC Hs gives normal product, ethyl neopentyl ether, with a second-order rate law indicating a direct >Sjv2 displacement mechanism. Bridged carbonium ions are not always formed as metastable intermediates, other structures being sometimes more stable. ... 

The second example shows that displacement reactions can be effected with neopentyl alcohol via a betylate. Of even greater interest, Sn2 displacements of chiral secondary alcohols can be effected via a betylate with high stereoselectivity 100% inversion is commonly observed. ... 

Methanesulfonale esters (mesylates). Mesylates can be prepared in 85-95% yield by the reaction at 0 10° of an alcohol in methylene chloride (or cyclohexane or pentane) containing a 50% molar excess of triethylamine with a 10% excess of mesyl chloride, added over a period of 5-10 min. The reaction probably involves the sulfene CH 2=S02, formed by dehydrochlorination of mesyl chloride. Tertiary and neopentyl alcohols can be esterihed by this procedure. Even reactive mesylates can be prepared if the temperature of the mesylate is kept at 0°. 

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