Magnesium iodide additive

Magnesium iodide is soluble in alcohols and many other organic solvents, and forms numerous addition compounds with alcohols, ethers, aldehydes, esters, and amines. One example is magnesium iodide dietherate [29964-67-8], Mgl2 prepared by gradual addition of iodine to a... 

Kost et al. studied the interaction of indole magnesium iodide with a number of cyclic anhydrides of dibasic organic acids.In addition to 254 the following. 3-indolyloxo acids were prepared in this manner -(3-indolyl)-8-oxovaleric acid (274), y-(3-indolyl)-y-oxocrotoiiic acid... 

A crystalline addition product of indole with picryl chloride (i.e. l-chloro-2,4,6-trinitrobenzene), together with an unidentified amorphous substance, were obtained by the action of picryl chloride on indole magnesium iodide, and analogous products were obtained in the reaction between the indole Grignard reagent and 1-chloro-2,4,5-trinitrobenzene. 

In 1961 Acheson and Hands obtained 3-methyl-l-(2-nitroethyl)-indole (354) in low yield by the addition of nitrocthylene to 3-methyl-indole magnesium iodide. These authors also obtained 5-benzyloxy-l,3-bis(2-nitroethyl)iiidole (355) and 5,6-dimethoxy-3-(2-nitroethyl)-indolo (356) by the action of nitrocthylene on 5-henzyloxy- and 5,G-dimethoxyindolc magnesium iodide, respectively. They excluded the ]jossibility that the products 354, 355, and 356 had the isomeric indolenine structures on the basis of their absorption spectra and chemical properties. 

Conjugate addition of methyl magnesium iodide in the presence of cuprous chloride to the enone (91) leads to the la-methyl product mesterolone (92) Although this is the thermodynamically unfavored axially disposed product, no possibility for isomerization exists in this case, since the ketone is once removed from this center. In an interesting synthesis of an oxa steroid, the enone (91) is first oxidized with lead tetraacetate the carbon at the 2 position is lost, affording the acid aldehyde. Reduction of this intermediate, also shown in the lactol form, with sodium borohydride affords the steroid lactone oxandrolone... 

The authors used a synthesis of 9,9-spirobitluorenes 32 which was developed by Clarksen and Gomberg [60] and which includes the addition of biphenyl-2-yl-magnesium iodide to fluorenone and subsequent cyclization with protic acids. To obtain 2,2,, 7,7 -arylated 9,9-spirobifluorenes 33, 9,9-spirobifluorene (32) was tetrabrominated [58] to yield 34 followed by a Suzuki-type aryl-aryl cross-coupling with various oligoaryl and oligoheteroaryl boronic acids to obtain the 2,2, 7,7 -tetraarylated derivatives 33. 

One of the first examples of this type of reaction, using a chiral alcohol as an auxiliary, was the asymmetric synthesis of 2-hydroxy-2-phenylpropanoic acid (atrolactic acid, 3, R1 =C6H5 R3 = CH3) by diastereoselective addition of methyl magnesium iodide to the men-thyl ester of phcnylglyoxylie acid4,5 (Table 22). 

Magnesium iodide has few commercial apphcations. The salt is used to prepare several addition compounds with organic solvents, some of which are used in organic synthesis. 

The copper-catalyzed conjugate addition of methyl magnesium iodide to cyclohexenone and trapping the enolate as its trimethylsilyl enol ether, followed by a trityl hexachloro-antinomate-catalyzed Mukaiyama reaction, is apphed to / -(—jcarvone. C-2, C-3 functionalized chiral cyclohexanones are converted into their a-cyano ketones, which are submitted to Robinson annulation with methyl vinyl ketone. Highly functionalized chiral decalones are obtained that can be used as starting compounds in the total synthesis of enantiomerically pure clerodanes (equation 70). 

Tri-tert-butyl-X -phosphorin24 readily reacts with bromine and with chlorine. Mach oxidizing with bromine in CCI4, could not isolate a crystalline product. The brown colour of the addition product of one mole Br2 to one mole 24 disappeared with water and the crystalline 2-hydro-phosphinic acid 85b could be isolated in 45% yield. Methyl-magnesium-iodide or red phosphorus yielded 2.4.6 tri-tert-butyl-X -phosphorin 24. It seems reasonable to suppose that on bromination l.l-dibromo-2.4.6-tri-tert-butyl-X -phosphorin was formed. 

Cydopentene oxide and 1 -methylcyclopentene oxide yield respectively Iran - 2 -methyloyclopentanol and a mixture of cie- and Iran 1.2-dixnethylcyclopentanol (Eq. 851) on treatment with methyl-magnesium iodide. 0 - . The latter could in principle be formed either by a preliminary isomerization to 2-methyJcyolopentanone, or by direct addition to the least-substituted epoxide carbon atom. These possibilities have not, however, been distinguished until now. 

The most important synthetic use of Grignard reagents and organolithium reagents is to form new carbon-carbon bonds by addition to polar multiple bonds, particularly carbonyl bonds. An example is the addition of methyl-magnesium iodide to methanal ... 

In similar fashion 30-ace toxy-20-oxo-5 -pregnane (Formula 275) gives the alcohol (Formula 276) (60%) and the alcohol (Formula 277) (20%) (113,114). The C-20 stereochemical assignments in Formulas 276 and 277 are based on the fact that addition of methyl magnesium iodide to... 

An improved synthesis of myrtine (23) from ( )-pelletierine (21) has been reported (Scheme 3) (c/. Vol. 9, p. 71). Stereospecific addition of methyl-magnesium iodide to the cyclic enaminone (22) gave ( )-myrtine, which was converted into natural (+)-myrtine by resolution with (-)-tartaric acid.31... 

Conjugate addition of indole to nitroolefins was carried out by thermal heating in a sealed tube or by addition of indolyl magnesium iodide or microwave irradiation. The results indicated that the microwave technique is most efficient with respect to time and yield (Scheme 26) [97]. 

To a stirred solution of methyl magnesium iodide (748 mg, 4.5 mmol) in ether (15 ml), diphenyliodonium bromide (722 mg, 2 mmol) and anhydrous nickel chloride (15 mg) were added all at once at room temperature, under nitrogen. The mixture was stirred for 20 min, unreacted methyl magnesium iodide was decomposed by addition of water, the reaction mixture was neutralized with 10% hydrochloric acid, washed with water, and the ether layer dried and concentrated. The residue was chromatographed (silica, petroleum ether) to give the pure biaryls. 

Penten-2-ol has been prepared by the addition of methyl magnesium iodide 4 or bromide 7 8 to crotonaldehyde and by the partial dehydration of pentandiol. ... 

A re-investigation of the Diels-Alder addition of butadiene to (-)-carvone has led to a reassignment of the structures of the major adduct (126) and the minor adduct (127).216 The isolation of the diol (128) on treating the ketone (129) with methyl-magnesium iodide is the result of a [2,3] sigmatropic rearrangement to (130) 217 this rearrangement may find application in artemisyl synthesis. 

Additional procedures which produce biaryls from aryl halides include catalytic hydrogenation, the action of the binary mixture magnesium-magnesium iodide, and the use of powdered iron in hydroxylated media. ... 

HC=C") and methyl magnesium iodide (CHs"). It is clear from Table 12 that addition occurs mainly in the sense leading... 

The diastereoselectivity has been enhanced by a transmetalation of the lithium enolate with Magnesium Bromide or Magnesium Iodide prior to the addition of benzaldehyde (eq 2). ... 

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