PUB - Publikationen an der Universität Bielefeld

Reaction of the ferriophosphane and ferrioarsane [CP*(CO)(2)FeE(SiMe3){C(OSiMe3)=CPh2}] (2a, E = P. 2b, E = As) with an equimolar amount of hexachloroethane proceeded smoothly to afford the chlorinated derivatives [Cp*(CO)(2)FeE(Cl){C(OSiMe3)= CPh2}] (3a, E = P; 3b, E = As). Only 3b could be converted into the pnictogen functionalized diazoalkane [CP*(CO)(2)FeAs-i {C(N-2)SiMe3}{C(OSiMe3)-CPh2}] (4b) by treatment with LiC(N-2)SiMe3. Upon gentle heating or irradiation, compound 4b as well as its antimony analogue 4c proved to be inert towards N-2-extrusion. Diazoalkane 4c and dialkyl acetylenedicarboxylates underwent [3 + 2] cycloadditions with the result of the (l-pyrazolyl)stibanes 9e and 9d. This process involved a sigmatropic migration of the antimony fragment from carbon to nitrogen. The novel products were characterized by elemental analyses and spectra (IR, H-1-, C-13, Si-29-, P-31-NMR). In addition the diazoalkanes 4b and 4e as well as the (l-pyrazolyl)stibane 9d were subjected to single crystal X-ray structure determinations. (C) 2002 Published by Elsevier Science B.V.