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Zincate reagents

The 1 1 zincate reagent is believed to be dimeric. At higher ratios of organolithium compounds, 2 1 and 3 1 species can be formed.174... [Pg.659]

Zincate reagents can add to imines with or without Lewis acid catalysis. Alkylimines require BF3 but imines of pyridine-2-carboxaldehyde react directly. If the imines are derived from chiral amines, diastereoselectivity is observed. Both a-phenylethyl amine and ethyl valinate have been tried. Higher enantioselectivity was observed with mixed magnesium reagents.175... [Pg.659]

Scheme 3.10. Diastereoselectivity in 1,4-addition of stannyl-lithium, cuprate, and zincate reagents to enantiopure 4-heteroatom-substituted 2-enoates [59],... Scheme 3.10. Diastereoselectivity in 1,4-addition of stannyl-lithium, cuprate, and zincate reagents to enantiopure 4-heteroatom-substituted 2-enoates [59],...
Some examples of the synthetic usefulness of zincate reagents in organic synthesis are stereoselective alkylation reactions of cyclic ketones, conjugate-addition reactions... [Pg.34]

Intramolecular addition of organot exchange and hydrolysis deliver propa different zincate reagents can lead to difl and cyclization. ... [Pg.272]

Intramolecular addition of organolithiums to an enyne moiety followed by Li/Zn exchange and hydrolysis deliver propargylcycloalkanes. The reaction of a halide with different zincate reagents can lead to different products, as shown by simple dehalogenation and cyclization. ... [Pg.273]

Conjugate Addition Reactions. The cuprate and zincate reagents lithium bis[dimethyl(phenyl)silyl]cuprate (75583-57-2) and lithium dimethyl[dimethyl(phenyl)silyl]-zincate (100112-20-7) are usually used in conjugate addition reactions, but PhMe2 SiLi can be used with catalytic amounts of dimethylzinc (eq More resistant substrates may employ the zincate produced in situ, with catalytic amounts of copper(I) additives, and aided by the cocatalyst Sc(OTf)3 (eq 18). ... [Pg.258]

Fig. 18 Solvent dependence on basicity of lithium zincate reagent... Fig. 18 Solvent dependence on basicity of lithium zincate reagent...
Barley HRL, Clegg W, Dale SH et al (2005) Alkali-metal-mediated zincation of ferrocene synthesis, structure, and reactivity of a lithium-TMP-zincate reagent. Angew Chem Int Ed 44 6018-6021. doi 10.1002/anie.200501560... [Pg.201]

See other pages where Zincate reagents is mentioned: [Pg.83]    [Pg.88]    [Pg.83]    [Pg.88]    [Pg.346]    [Pg.112]    [Pg.165]    [Pg.83]    [Pg.88]    [Pg.782]    [Pg.606]    [Pg.234]    [Pg.150]   
See also in sourсe #XX -- [ Pg.112 ]



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