Ketones lateral lithiation

When the ketone cannot be enolized, lateral lithiation appears to be very easy 524 is lithiated by LDA at -78 °C (Scheme 205f >. 

Ketones may direct lateral lithiation even if the ketone itself is enolised enolates appear to have moderate lateral-directing ability. Mesityl ketone 433, for example, yields 434 after silylation - BuLi is successful here because of the extreme steric hindrance around the carbonyl group.396 The lithium enolate can equally well be made from less hindered ketones by starting with a silyl enol ether.396... 

Lateral metallation at C-2(a) of l-/ftt-butoxycarbonyl-2-methylimidazoline 709 (Scheme 173) with r f-BuLi results in the formation of a bright yellow lithiated intermediate that reacts with alkyl halides, diphenyldiselenide, and phosphoryl chlorides to give 710. In the case of reaction with esters, the conjugated ketones 711 are formed <2000T2061>. In the case of acylation with esters, conjugated enamino-ketones were the tautomer isolated. Further alkylation is also possible under similar conditions, to give 712. 

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