HMPT Hexamethylphosphorous triamide

Hexamethylphosphoric triamide (HMPT) is a high-boiling solvent particularly satisfactory for dissolving metals or organometallic compounds. It has been found to be an ideal solvent in which to conduct the reduction of a,jS-unsaturated ketones by alkali metals. 

Cuprous iodide catalyzes the reaction of various alkyl chlorides, bromides, and iodides in hexamethylphosphoric triamide (HMPT), to give the complexed product RaSnXj, which can then be further alkylated with a Grignard reagent, or can be hydrolyzed to the oxide and converted into various other compounds, R2SnY2 (43). This promises to be a useful laboratory method, e.g.,... 

The simple hexaalkylditins, RsSnSnRs, do not disproportionate on heating, but, in oxolane (tetrahydrofuran) or acetonitrile in the presence of a base such as a Grignard reagent, or in the more strongly basic solvent hexamethylphosphoric triamide (HMPT), disproportionation readily occurs at room temperature, and, in HMPT, addition occurs to such alkynes as phenylacetylene and diphenylbutadiyne. The disproportionation is considered to proceed by nucleophilic attack upon tin (259, 260), e.g.,... 

Hexamethylphosphoric triamide (HMPT), in anionic polymerization of cyclic siloxanes, 22 560 Hexamine, 12 112 Hexanal... 

Hexamethylphosphoric triamide (HMPT) [680-31-9] M 179.2, f.p. 7.2°, b 68-70°/lmm, 235°/760mm, d 1.024, n 1.460. The industrial synthesis is usually by treatment of POCI3 with excess of dimethylamine in isopropyl ether. Impurities are water, dimethylamine and its hydrochloride. It is purified by refluxing over BaO or CaO at about 4mm pressure in an atmosphere of nitrogen for several hours, then distd from sodium at the same pressure. The middle fraction (b ca 90°) is collected, refluxed over sodium under reduced pressure under nitrogen and distd. It is kept in the dark under nitrogen, and stored in solid CO2. Can also be stored over 4A molecular sieves. 

Dipolar aprotic solvent. This cyclic urea can serve as a substitute for the carcinogenic hexamethylphosphoric triamide (HMPT) in reactions of highly nucleophilic and basic reagents. It mimics the effect of HMPT in Wittig olefination und in selective generation of various enolates. It forms homogeneous solutions with I IIF even at -78°. ... 

The use of dimethyl sulphoxide in organic chemistry has revealed the profound influence of solvent on the course and the rates of organic reactions. The striking discovery, in the early 1960 s, that certain dipolar aprotic solvents such as dimethylformamide (DMF), tetrahydrothiophene-1,1-dioxide (sulfolane), hexamethylphosphor-triamide (HMPT), as well as DMSO, could result in certain instances in rate enhancements of the order of 1010 relative to hydroxylic solvents led to a re-appraisal of the then established theories of medium effects. 

The reaction of allylic alcohols and aryl halides in the presence of a palladium catalyst has been used in the past to prepare various 0-arylal-dehydes. The procedure described here is essentially that of Heck and Melpolder.3 A similar reaction has been carried out with bromobenzene and 2-methyl-2-propen-l-ol in hexamethylphosphoric triamide (HMPT) as solvent with sodium bicarbonate as base. A variety of other bases have also been used.4 2-Methyl-3-phenylpropanal has been prepared by reacting palladium acetate and phenylmercuric acetate with 2-methyl-2-propen-l-ol.5... 

Indeed, in diethyl ether, lithium dimethylcuprate usually reacts with the a-enone group to give a methyl-substituted bromo ketone. Addition of hexamethylphosphoric triamide (HMPT), however, slows down this reaction to such an extent that displacement of the bromo substituent takes place [698], Another remarkable example of the influence of HMPT on chemoselectivity is the reaction of an arsonium ylide, Ph3As= CH-CH=CH-Ph, with benzaldehyde in tetrahydrofuran solution, yielding either an epoxide (in THE) or an alkene (in THF/HMPT) [699],... 

Since donor numbers are defined in the non-SI unit kcal mol Marcus has recommended the use of dimensionless normalized donor numbers DN, which are defined as DN = DNl 38.8 kcal mol ) [133]. The non-donor solvent 1,2-dichloroethane [DN = DN = 0.0) and the strong donor solvent hexamethylphosphoric triamide (HMPT DN = 38.8 kcal mol DN = 1.0) have been used to fix the DN scale. Although solvents with higher donicity than HMPT are known, it is expedient to choose this EPD solvent with the highest directly, i.e. calorimetrically, determined DN value as the second reference solvent [133]. The normalized DN values are also included in Table 2-3 in Section 2.2.6. 

The reaction of ate complexes (24), formed from trialkylboranes and trimethyl-silylpropargyl phenyl ether, with a mixture of acetic acid and hexamethylphosphoric triamide (HMPT) gives trimethylsilylacetylenes (25) selectively (Eq. 54) whereas the corresponding trimethylsilylallenes (26) are selectively prepared by the reaction with sodium methoxide instead of acetic acid and HMPT (Eq. 54) In the latter, when primary alkylboranes are used, the corresponding allene derivatives are obtain in high purity, but secondary alkylboranes give reverse ratios of the isomer distribution. 

Hexamethylphosphorous triamide (HMPT) [1608-26-0] M 163.2, m 7.2 , b 49-51 /12mm, 162-164 /12mm, d 0.989, n 1.466. It may contain more than 1% of phosphoric triamide. The yellow oil is first distd at atm press then under reduced press and stored under N2. It is air sensitive, TOXIC, should not be inhaled and is absorbed through the skin. [Mark Org Synth Coll Vol V 602 1973.]... 

The result with allyllithium 23 a differs only insignificantly from that of an earlier report (10.5 kcal/mol)25>. Complexation of 23 a with TMEDA does not influence the rate of exchange. Hexamethylphosphoric triamide (HMPT), 15-crown-5 ether and [2.1.1]cryptand in tetrahydrofuran (THF) led to rapid decomposition of 23a. Addition of n-butyllithium had essentially no effect on the barrier. Since the 13C NMR chemical shifts of 23 a are independent of the solvent, it is assumed that 23 a exists as a contact ion pair or higher aggregate in the NMR experiments. (The other alkali metals should also form contact ion pairs with the allyl anion because of their well-known tendency to form contact ion pairs even more readily than the lithium cation 26)). 

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