Ethylmagnesium Bromide-Copper(I) Iodide1

EtMgBr + CuI

[925-90-6]  · C2H5BrMg  · Ethylmagnesium Bromide-Copper(I) Iodide  · (MW 133.28) (CuI)

[7681-65-4]  · CuI  · Ethylmagnesium Bromide-Copper(I) Iodide  · (MW 190.45)

(used for preparing allenic,2 alkenic,2 and allylic alcohols;3 reduces alkynes to alkenes;4 reduces alkenyl sulfoxides to alkenyl sulfides5)

Preparative Methods: prepared in situ under anhydrous conditions by reacting Ethylmagnesium Bromide (1) and Copper(I) Iodide (2) in varying molar ratios.

Handling, Storage, and Precautions: use in a fume hood.

SN2 Alkylations: Preparation of Allenic, Alkenic, and Allylic Alcohols.

Allenic and alkenic alcohols have been prepared by reacting methoxy-substituted alkynyl and alkenic alcohols, respectively, with a preformed solution of ethylmagnesium bromide-copper(I) iodide (eqs 1 and 2).2

Kang et al.3 used (1) and catalytic (2) in the presence of Boron Trifluoride Etherate to prepare a chiral allylic alcohol from a cyclic carbonate (eq 3). This conversion represents a 1,3-chirality transfer method.

Reduction of Alkynes.

Alkynes are reduced to the corresponding cis-alkenes by treatment with excess (1) and (2) (2:1) at -30 °C in ether (eqs 4-6).4

Reduction of Alkenyl Sulfoxides.

Treatment of a,b-unsaturated sulfoxides with (1) in the presence of catalytic (2) in ether at 0 °C affords the corresponding alkenyl sulfides with the original configuration about the vinyl group (eq 7).5

1. For a recent review of organocopper reagents, see: Lipshutz, B. H.; Sengupta, S. OR 1992, 41, 135.
2. Claesson, A.; Tamnefors, I.; Olsson, L. TL 1975, 1509.
3. Kang, S.; Lee, D.; Sim, H.; Lim, J. TL 1993, 91.
4. Crandall, J. K.; Collonges, F. JOC 1976, 41, 4089.
5. Posner, G. H.; Tang, P. JOC 1978, 43, 1978.

Michael N. Greco

The R. W. Johnson Pharmaceutical Research Institute, Spring House, PA, USA

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