Isopropyl magnesium bromide

Abstract. Grignard reactions are of utmost importance in organic synthesis (Lee, 2005), and finding the prime conditions under which to conduct these reactions is really crucial to their usefulness. This work looks at the effects of time, and temperature on yield in the reaction of isopropyl magnesium bromide with 4-methoxyben-zaldehyde to produce l-(4-methoxyphenyl)-2-methylpropan-l-ol. The reaction was first run for 10 min at 25, 50, 75, and 80 °C. Next it was run at 80 °C for 10, 20, and 30 min (see Methods section for more details). Highest yields (85%) were obtained at 80 °C with 10-20 min reaction times. Utilizing conditions that optimize yields will improve the economic practicality of these reactions, and increase their usefulness as a synthetic tool. 

The stereoselective Horner-Wadsworth-Emmons reaction of aldehydes with 2-fluoro-2-diethylphosphonoacetic acid utilizing isopropyl magnesium bromide afforded (Z)-a-fluoro-a,j8-unsaturated carboxylates (42) as the major products in 81-98% yield [58] (Scheme 14). 

Corrected for 85.1 % optical purity of chiral imine. p Recorded at 22 °C. q Metalation with isopropyl magnesium bromide. 

To prove this hypothesis a suitable substrate, l-diazo-3-methyl-3-[(E)-phenyldiazenyl]butan-2-one (42) was used. Methyl 2-(2-arylhydrazino)-2-methylpropanoate (39) reacting with a bulky Grignard reagent like isopropyl magnesium bromide gives 4,4-dimethyl-2-phenyl-l,2-diazeti-din-3-one 40 (87TL6577). Oxidation with ferf-butyl hypochlorite converts diazetidinone 40 into 2-methyl-2-(phenyldiazenyl)propanoyl chloride 41, which upon treatment with diazomethane affords the desired diazo ketone 42 (Scheme 8) (98ACE2229). 

A versatile method for the preparation of olefin metal complexes has been developed by E. 0. Fischer and his coworkers a Grignard reagent (preferably isopropyl magnesium bromide) is reacted with a mixture of a transition metal halide and an olefin in ether. Subsequent irradiation increases the yield and accelerates the formation of the corresponding metal complexes. 

Moffatt oxidation of 11 gave 12, which, without isolation, was treated with isopropyl-magnesium bromide to give 11 (21%), 13 (35%) and 14 (30%). The undesired product 13 could be converted into the desired product 14 via oxidation-reduction process in 70% overall yield. Removal of the silyl protecting group from 14 with TFA afforded the lactam 15, which underwent ozonolysis followed by selective oxidation of the resulting aldehyde to afford the carboxylic acid 16. The latter, without isolation, was coupled with... 

For obtaining branched chain members in the cardol series such as Adipostatin B, isotetradecyl bromide has been synthesised from isopropyl magnesium bromide and 11-bromundecanol (protected as the tetrahydropyranyl derivative) in the presence of lithium cuprate (U2CUCI4). The usual reaction with 3,5-dimethoxybenzaldehyde followed by hydrogenolysis and demethylation afforded the required product (ref. 100). 

The interaction between the sodium salt of phenylacetic acid and isopropyl magnesium bromide results into a doubly charged species known as the Ivanov reagent. This product on treatment with cyclopentanone affords aldol condensation to yield the corresponding hydroxy acid. The resulting product on being subjected to alkylation with N-(2-chloro-ethyl)-dimethylamine gives the desired official compound. 

Explain why the alcohol 5 is the major diastereomer in the addition of isopropyl magnesium bromide to the ketone 4. Account for the formation of the alcohol 6 in this reaction and explain the stereochemistry of this product. 

Cyclohepta-l,3-diene and ruthenium(iii) chloride trihydrate react in the presence of zinc dust and ethanol to give (329). Complex (329) was also obtained from [(C7Hio)RuCl2] and isopropyl magnesium bromide in the presence of cyclohepta-... 

Lithium, THF, chlorodimethylphenylsilane, a solution of isopropyl-magnesium bromide in diethyl ether, 1,2-dichloro-l, 1,2,2-tetramethyldisilane, saturated aqueous ammonium chloride, diethyl ether, brine, anhydrous magnesium sulfate, silica gel, hexane. 

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