Weber, Lothar; Uthmann, Stefan; Stammler, Hans-Georg; Neumann, Beate; Schoeller, Wolfgang W.; Boese, Roland; Blaser, Dieter:

Reactivity of carbonyl-functionalized phosphaalkenes RC(O)P:C(NMe2)2 (R = tBu, Ph) towards electrophiles.

In: European Journal of Inorganic Chemistry, (1999) ; Nr. 12, S. 2369-2381
ISSN: 1434-1948
Zeitschriftenaufsatz / Fach: Chemie
Abstract:
The reaction of the carbonyl-functionalized phosphaalkenes RC(O)P:C(NMe2)2 (R = tBu, Ph) with protic acids and alkylating reagents occurred at the 2-coordinate P atom to give the corresponding phosphinyl-substituted carbocations. In contrast, treatment with Me3SiO3SCF3 resulted in attack at the O atom by the silyl group, and the formation of [RC(OSiMe3):PC(NMe2)2]+CF3SO3-. Similarly, the Lewis acids B(C6F5)3, Al(tBu)2Cl, and AlMe3 were ligated to the O atom of the CO group. Two equiv GaMe3 were added to the O and P atom of the phosphaalkene to yield the thermolabile complexes [RC(OGaMe3):P(GaMe3)C(NMe2)2]. In contrast, one mol. of InMe3 was bound to the P center of the P compd. Reaction of the phosphaalkenes with [Ni(CO)4], [Fe2(CO)9], or [{(Z)-cyclooctene}Cr(CO)5] also took place at the pnicogen atom, resulting in [RC(O)P{M(CO)n}C(NMe2)2] (R = tBu, Ph with M = Ni, n = 3; Fe, n = 4; Cr, n = 5). X-ray structures of (C6F5)3B-OCPh:PC+(NMe2)2, Cl2(tBu)AlB-OCPh:PC+(NMe2)2, [tBuC(OGaMe3):P(GaMe3)C(NMe2)2], tBuC(O)P(In-Me3)C+(NMe2)2, and tBuC(O)P[Cr-(CO)5]C+(NMe2)2 are reported.