Deprotonations sodium hexamethyldisilazide

Tetrahydro-l,4-oxazin-2-ones can be deprotonated and then reacted with electrophiles. Thus, for example, the nonlabeled analog of compound 81 was deprotonated at the 3-position with sodium hexamethyldisilazide and ethylated using ethyl iodide. The reaction was performed in a 1 10 mixture of hexamethylphosphoramide (HMPA) and tetrahydrofuran <1998T10419>. If a dihalide is used and the oxazine has a free 4-nitrogen, cycloalkylation can be achieved as shown in the reaction of 219 to give 220 (Equation 17) <1993LA477>. 

The acid is converted with thionyl chloride into the corresponding acid chloride, which reacts in a second step with the anion of the Lvans oxazolidinone 3714 to give an /V-acyloxazolidinone. This is then deprotonated with sodium hexamethyldisilazide and subsequently alkylated selectively with methyl iodide to produce compound 8. 

Deprotonation of the benzo-l,3-dithiole dioxide 259 with -BuLi or sodium hexamethyldisilazide (NaHMDS) and subsequent reaction of the resulting carbanion with pivaldehyde gave a mixture of products 260 and 261 (Equation 21) <1995JO02174>. 

The Julia-Kocienski olefination of heterocyclic sulfones and aldehydes, which is an alternative to the modified Julia olefination, forms alkenes with good -selectivity. First, sulfone 54 is deprotonated in the a-position to the sulfur by sodium hexamethyldisilazide (NaHMDS) and the sulfur-stabilized anion 55 then adds to the alde-... 

Ojima developed a second route to docetaxel, in which the side-chain was introduced by deprotonation with sodium hexamethyldisilazide and reaction with a /3-lactam. [329]... 

Mitsunobu reaction with alcohols and subsequent oxidation with MCPBA. Deprotonation of such a sulfone with sodium or potassium hexamethyldisilazide in DME followed by reaction with an aldehyde results in an ( )-alkene. 

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