P-functional phosphaalkenes with C-isopropyldimethylsilyl groups, and a sterically stabilized P-cyano phosphaalkene

GRAPHICAL ABSTRACT

ABSTRACT

The dehydrochlorination of the dichlorophosphane (iPrMe₂Si)₂C(H)PCl₂ (2) with 1,4-diazabicyclo[2.2.2]octane (DBO) provides the P-chlorophosphaalkene (iPrMe₂Si)₂C=PCl (3). Halide exchange reactions of 3 with AgBF₄, with Me₃SiBr, and with Me₃SiI lead to the P-halogenophosphaalkenes (iPrMe₂Si)₂C=PX (X = F: 4; X = Br: 5; X = I: 6). From the reaction of 3 with AgCN, the sterically stabilized P-cyanophosphaalkene (iPrMe₂Si)₂C=P-CN (7) was isolated. The structures of the related P-fluorenylphosphaalkene 9 (from 3 with fluorenyllithium) and of the P-selenophosphaalkenes (iPrMe₂Si)₂C = PSe(2,4,6-tBu₃C₆H₂) (10) and [(iPrMe₂Si)₂C=P]₂Se (11) were determined by X-ray crystallography.

KEYWORDS:

• P-halogeno phosphaalkenes
• P-cyano phosphaalkenes
• P-seleno phosphaalkenes
• X-ray crystallography
• ³¹P-NMR

Acknowledgments

We thank Ms. D. Döring and Dr. U. Papke (mass spectrometry) and Professor L. Ernst (NMR spectroscopy) for support.