Transition Metal Substituted Acyl Phosphanes and Phosphaalkenes. 28.¹ Reactivity of Metallophosphaalkenes (η⁵-C₅Me₅)(CO)₂FePCR¹₂ (R¹ = SiMe₃, NMe₂) toward Methyl and Ethyl Propiolate

Abstract

The metallophosphaalkene (η 5 -C 5 Me 5 )(CO) 2 FePdC (SiMe 3 ) 2 (1) undergoes reaction with 2 equiv of alkyl propiolates HCtCCO 2 R 2 (R 2) Me, Et) to afford the novel bicyclic) Me (8c), Et (8d)]. In contrast to this, metallophosphaalkene (η 5 -C 5 Me 5 )(CO) 2 FePdC(NMe 2 ) 2 (2) smoothly adds 3 equiv of the propiolates with formation of the spirobicyclic compounds) Me (10c), Et (10d)]. Treatment of equivalent amounts of methyl propiolate and 2 gave a mixture of P-metallo-1-phosphabutadiene (η 5 -C 5 Me 5 )(CO) 2 FePdCHC(CO 2 Me)dC(NMe 2 ) 2 (6c) and metalloheterocycle (η 5 -C 5 Me 5 )(CO)FeP[dC(NMe 2 ) 2 ]CHdCH(CO 2 Me)CdO (5c). The molecular structure of 8c was determined by single-crystal X-ray diffraction.

P–C and C–C Coupling Processes in the Reactions of the Phosphinidene-Bridged Complex [Fe2(η5-C5H5)2(μ-PCy)(μ-CO)(CO)2] with Alkynes

“…1590 cm –1 ), and these groups give rise in the case of cis -3a to deshielded and 31 P-coupled 13 C NMR diagnostic resonances at 260.9 and 257.2 ppm (bridging CO and acyl) and 215.0 ppm (terminal CO). We note that comparably deshielded acyl resonances have been reported for mononuclear phosphine-acyl complexes of the type [FeCp*­{κ 2 -(RR′C)­PCRCR′C­(O)}­(CO)] . The phosphide P nucleus in these compounds gives rise to a strongly deshielded resonance at ca.…”

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…Related to the above [2+2] addition of 31 and 32 in Scheme 4, with sort of reversed premises, is the nonconcerted [2+2] addition of activated alkynes to the PdC double bond in metallophosphaalkenes 44 in Scheme 6. 123,124 The initial [2+2] adduct 45, which cannot be observed spectroscopically, undergoes spontaneous cycloreversion to the stable (R 1…”

“…Related to the above [2+2] addition of 31 and 32 in Scheme , with sort of reversed premises, is the nonconcerted [2+2] addition of activated alkynes to the PC double bond in metallophosphaalkenes 44 in Scheme . , The initial [2+2] adduct 45 , which cannot be observed spectroscopically, undergoes spontaneous cycloreversion to the stable (R 1 = R 2 = COOMe) metallophosphabutadiene 46a . The phosphabutadiene 46b (R 1 = Me, R 2 = COOMe) slowly cyclizes with elimination of dimethylamine, giving 41% isolated yield of 47b .…”

Zur Reaktivität des Ferriophosphaalkens (Z)-[Cp*(CO)2FeP=C(tBu)NMe2] gegenüber Propiolsäureestern HC≡C-CO2R (R=Me, Et) und Acetylendicarbonsäureestern RO2C-C≡C-CO2R (R=Me, Et, tBu)

“…Verbindung I addiert zwei Moläquivalente eines Propiolsäureesters zu Komplex VI [8], während die Umsetzung von II mit überschüssigem Propiolsäure-methylester 2a zu einem Gemisch der Produkte VII und VIII führt (Schema 2) [8].…”