Isopropylmagnesium Bromide1

(X = Br)

[920-39-8]  · C3H7BrMg  · Isopropylmagnesium Bromide  · (MW 147.31) (X = Cl)

[1068-55-9]  · C3H7ClMg  · Isopropylmagnesium Chloride  · (MW 102.86)

(adds to many unsaturated functional groups; isopropyl can displace halide and like groups; functions as a strong base and a Lewis acid1b-f)

Physical Data: i-PrMgCl is mainly dimeric in Et2O.2

Solubility: i-PrMgBr and i-PrMgCl are sol Et2O, THF; insol hydrocarbons.

Form Supplied in: solutions of i-PrMgCl in Et2O and THF are commercially available.

Analysis of Reagent Purity: see Methylmagnesium Bromide.

Preparative Methods: in spite of the commercial availability of i-PrMgCl solutions, i-PrMgBr4 and i-PrMgCl are often prepared from reaction of an isopropyl halide and Mg, usually in Et2O or THF.1c,e,3

Handling, Storage, and Precautions: see Methylmagnesium Bromide. Isopropyl Grignard reagents do not significantly attack Et2O or THF at normal reaction temperatures.

Representative Applications.1b-f

See also Methylmagnesium Bromide. An isopropyl Grignard reagent is used most frequently in reactions that result in attachment of its organic group to an electrophilic carbon atom of the substrate, most often of a carbonyl group, nitrile, or other unsaturated function. The reaction with a chiral ketone (eq 1) serves as a reminder that, particularly with hindered substrates, isopropyl and other secondary Grignard reagents (see also t-Butylmagnesium Chloride) can act significantly by transfer of an H atom rather than an alkyl group.5

Related Reagents.

s-Butyllithium; t-Butylmagnesium Chloride; Methylmagnesium Bromide.

1. (a) Lindsell, W. E. In Comprehensive Organometallic Chemistry; Wilkinson G.; Stone, F. G. A.; Abel, E. W., Eds.; Pergamon: Oxford, 1982; Chapter 4. (b) Wakefield, B. J. In Comprehensive Organometallic Chemistry; Wilkinson G.; Stone, F. G. A.; Abel, E. W., Eds.; Pergamon: Oxford, 1982; Chapter 44. (c) Nützel, K. MOC 1973, 13/2a, 47. (d) Raston, C. L.; Salem, G. In The Chemistry of the Metal-Carbon Bond; Hartley, F. R., Ed.; Wiley: Chichester, 1987; Vol. 4, Chapter 2. (e) Old but still extremely useful is: Kharasch, M.; Reinmuth, O. Grignard Reactions of Nonmetallic Substances; Prentice-Hall: New York, 1954. (f) Ioffe, S. T.; Nesmeyanov, A. N. The Organic Compounds of Magnesium, Beryllium, Calcium, Strontium and Barium; North-Holland: Amsterdam, 1967.
2. Walker, F. W.; Ashby, E. C. JACS 1969, 91, 3845.
3. Bickelhaupt, F. In Inorganic Reactions and Methods; Hagen, A. P., Ed.; VCH: New York, 1989; Vol. 10, Section; FF 1967, 1, 415.
4. Drake, N. L.; Cooke, G. B. OS 1943, 2, 406.
5. Maglioli, P.; De Lucchi, O.; Delogu, G.; Valle, G. TA 1992, 3, 365.

Herman G. Richey, Jr.

The Pennsylvania State University, University Park, PA, USA

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