Ketones, reaction with hexamethyldisilazide

This reaction can sometimes be useful in synthesis. In the Honda et al. formal synthesis of securinine,2h N-benzylamino-ketone (97) was treated with lithium hexamethyldisilazide and then sorbic anhydride. This gave dienyl ester 98 by O-alkylation of the initially formed enolate anion. When the nitrogen protecting group was... 

Both sodium t-butoxide and potassium hexamethyldisilazide were used in palladium-catalyzed ketone arylations. While reactions involving electron-neutral or electron-rich aryl halides were more selective for monoarylation when JCHMDS was used, sodium f-butoxide gave good selectivity with electron-poor aryl halides, without direct decomposition of the aryl halide. Bis(diph-enylphosphino)ferrocene-ligated palladium complexes were... 

The products of the reaction of ketones with lithium hexamethyldisilazide have been studied by Collum and co-workers by an extensive use of the Li and NMR spectroscopy Vun couplings have been found to be particularly useful. 

The tricyclic ketone (387) which has been suggested as an intermediate in the transformation of the exo-2-bromobicyclo[3,2,0]heptane-6-ones to anti-7-substituted bicyclo[2,2,l]heptan-2-ones has been isolated. Treatment of (388) with sodium hexamethyldisilazide gave (387), whose structure was confirmed by single-crystal J -ray crystallography. Reaction of (387) with potassium cyanide in methanol containing a catalytic amount of methoxide gave anti-7-cyano-5-bromobicyclo[2,2,l]-heptanone (389). The availability of (387) should allow an increase in the range of... 

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