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7.6.11.2.2 Variation 2: Nickel-Catalyzed Coupling of Grignard Reagents with Allyl Compounds

DOI: 10.1055/sos-SD-007-00562

Takahashi, T.; Liu, Y.Science of Synthesis, (20047599.

Various allyl compounds have been utilized in coupling reactions with Grignard reagents, including allylic ethers,[‌18‌‌21‌] alcohols,[‌22‌,‌23‌] halides,[‌24‌] sulfides,[‌25‌] acetals,[‌18‌,‌26‌] selenides,[‌27‌] carbonates,[‌28‌] and phosphates.[‌29‌] In these reactions, regioselectivity and stereoselectivity are important targets. Methylation of cis- or trans-4-methylcyclohex-2-en-1-ol with methylmagnesium iodide using [1,2-bis(diphenylphosphino)ethane]dichloronickel(II) as a catalyst gives mixtures of 3,6- and 3,4-dimethylcyclohexene.[‌23‌] From the cis-isomer cis-5, only the trans-isomers trans-6 and trans-7 are obtained as products (Scheme 4). Alkylation of allylic alcohols by Grignard reagents in the presence of a nickel catalyst is stereospecific and takes place on the side of the ring opposite to that of the hydroxy group (anti attack). See also Science of Synthesis Vol.1 [Compounds with Transition MetalCarbon π-Bonds and Compounds of Groups 108 (Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) (Section 1.1.2.7.3)].

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