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Hydrolytic lithium diisopropylamide

Silyl Ketene Acetals. The lithium enolates of esters may be trapped with TBDMSCl to prepare the corresponding ketene silyl acetals. The resulting TBDMS ketene acetals are more stable than the corresponding TMS ketene acetals and have a greater preference for O- vs. C-silylation products. When TMSCl was used to trap the enolate of methyl acetate, a 65 35 ratio of O- to C-silated products was obtained. In addition, O-(TMS) sUyl ketene acetals are thermally and hydrolytically unstable. However, similar treatment of lithium enolates with TBDMSCl provided the corresponding O-(TBDMS) silyl ketene acetals exclusively (eq 3). The 0-TBDMS ketene acetals generally survive extraction from cold aqueous acid, lithium diisopropylamide was found to be satisfactory for the preparation of the ester enolates. The lower reactivity of TBDMSCl requires that the enol silation be performed at 0 °C with added HMPA. ... [Pg.111]

See other pages where Hydrolytic lithium diisopropylamide is mentioned: [Pg.60]    [Pg.76]    [Pg.142]    [Pg.60]    [Pg.405]    [Pg.92]    [Pg.688]    [Pg.688]   
See also in sourсe #XX -- [ Pg.92 ]



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Diisopropylamide

Hydrolytic

Lithium diisopropylamide

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