silicon and trifluoroacetamide

[reaction: see text] Chiral N-acylhydrazones derived from commercially available 4-benzyl-2-oxazolidinone provide a rigid, conformationally restricted template to impart facial selectivity in additions to C=N bonds. In the presence of indium(III) trifluoromethanesulfonate [In(OTf)3], N-acylhydrazones undergo highly diastereoselective fluoride-initiated additions of allylsilanes (aza-Sakurai reaction). Mechanistic studies including control experiments and comparisons with allyltributylstannane, allylmagnesium bromide, and allylindium species implicate a dual activation mechanism involving addition of an allylfluorosilicate species to a chelate formed from In(OTf)3 and the chiral N-acylhydrazone. The N-N bonds of the adducts are readily cleaved in a two-step protocol to provide synthetically useful homoallylic N-trifluoroacetamides. Further elaboration of the latter compounds through Wacker oxidation and olefin metathesis provides diversely functionalized building blocks and expands the potential applications of this C-C bond construction approach to asymmetric amine synthesis.

Topics: Acetamides; Acylation; Aldehydes; Alkenes; Amines; Electrons; Fluoroacetates; Hydrazones; Ketones; Magnetic Resonance Spectroscopy; Molecular Structure; Nitrogen; Silanes; Silicon; Stereoisomerism; Trifluoroacetic Acid

We propose a technique for measuring valproic acid using gas phase chromatography with a OV1 column, classically used for steroid assays. The valproic acid is extracted directly from the plasma by either from a small test sample (200 microliters). The silylation is performed instantaneously at the level of the injector. The accuracy and precision of the method are excellent; there is no interference with other anti-convulsants. The technique is simple, very rapid and not expensive; it should find a wide application in routine practice.

Topics: Acetamides; Chromatography, Gas; Fluoroacetates; Humans; Microchemistry; Silicon; Trimethylsilyl Compounds; Valproic Acid