Umsetzungen von Metall‐ und Metalloidverbindungen mit mehrfunktionellen Molekülen, XX. Reaktionen von N ‐(Trimethylsilyl)carbonamiden mit Dihalogen‐organylboranen bzw. Trihalogenboranen

Abstract

LaRt man 2,2,2-Trihalogen-N-(trimethylsilyl)acetamide rnit Trichlorboran, Trihromboran oder Dihalogenorganylboranen reagieren, so erhslt man das Ringsystem des l-Oxa-3-azonia-5-aza-2-borata-3,5-cyclohexadiens (1 -6). Bei der Umsetzung von 2,2,2-Trifluor-N-(trimethylsilyl)-acetamid mit Trifluorboran entsteht das Addukt 7 aus Trifluoracetamid und Trifluorboran. Die Reaktion von 2-Chlor-N-(trimethylsilyl)acetamid mit Butyldichlorboran ergibt den Chloracetimidsaure-horylester 8. Dazu analoge Verbindungen werden erhalten, wenn man in 3 das Chlor mit AgCN oder NaN, reagieren lint ( + 9, 10) oder lithiiertes 2,2,2-Trifluor-N-(trimethylsilyl)-acetamid mit Dihalogenorganylboranen umsetzt (+ 14, 15). Durch Spaltung der beiden Si -NBindungen im l-Oxa-3,5-diaza-2,4-disila-5-cyclohexen 11 durch Dihalogenorganylborane entstehen die entsprechenden l-Oxa-3,5-diaza-2,4-dibora-5-cyclohexen-Verbindungen (12, 13). Die Verbindungen werden analytisch und spektroskopisch (NMR: 'H, "B, "F; MS; IR) charakterisiert. ') Reactions of N-(Trimethylsilyl)earboxamides with Dihalogenoorganylboranes and Trihalogenoboranes 2,2,2-Trihalogeno-N-(trimethylsilyl)acetamides react with trichloroborane, tribromoborane, or dihalogenoorganylhoranes to give the ring system of l-oxa-3-azonia-5-aza-2-borata-3,5-cyclohexadiene (1 -6). Trifluoroborane reacts with 2,2,2-trifluoro-N-(trimethylsilyl)acetamide to yield the trifluoroborane adduct 7 of trifluoroacetamide. The reaction of 2-chloro-N-(trimethyIsilyl)-acetamide with butyldichloroborane leads to the formation of the boryl chloroacetimidate 8. Analogous compounds are also obtained by substitution reactions of the chlorine atom in 3 with AgCN and NaN, (+ 9, 10) or by the reaction of lithiated 2,2,2-trifluoro-N-(trimethylsilyl)acetamide with dihalogenoorganylboranes ( + 14, 15). Cleavage of both Si -N bonds in 1-oxa-3,5-diaza-2,4-disila-5-cyclohexene 11 by dihalogenoorganylboranes leads to the corresponding 1-oxa-3,5-diaza-2,4-dibora-5-cycloherenes (12, 13). The 'H, "B, and 19F NMR, mass and IR spectra are reported. Reaction of Metal and Metalloid Compounds with Polyfunctional Molecules, XX

Cyclic Ketiminoboranes

“…Two signals NMR references are (CH 3 ) 4 Si and BF 3 · Et 2 O. Ϫ Mass spectra for the methyl group of the isopropylamino substituents in were obtained with a Finnigan MAT 8200 plus spectrometer using the values reported for a B(NϭCH 2 ) 3 [5] . One has to con- 8 high-field shift in the 11 B-NMR spectrum. (5), c ϭ 32.990(17) Å , β ϭ 95.12(2), Z ϭ 4; 4599 reflections, R1 ϭ CH 2 Cl 2 was added within 1 h dropwise to a solution of 1.76 g (5 mmol) 3 in 50 mL of CH 2 Cl 2 at room temp.…”

“…A cumulene-like arrangement is difficult to verify in This shift is a consequence of the orbital symmetry, which small cyclic molecules, in which the CϭNϪB unit may be does not allow an interaction of the free electron-pair of compared with an allyl cation. To our knowledge only a the ketiminonitrogen atom and the p z orbital of the boron few six-membered heterocycles such as A؊C [6,7,8] with an atom in the five-membered heterocycle. With four π elecincorporated CϭNϪB unit have been described.…”