Syntheses and properties of phosphino- and phosphinatopyrroles

Abstract

. Can. J. Chem. 54, 2706Chem. 54, (1976.The syntheses of P-N bonded pyrrolyl-and 2,5-dimethylpyrrolylphosphines +,P(py),-, and +ZP(Mezpy)3-z (x = 0-2) and the oxy derivatives py3PO and (Mezpy)2P(O)Cl by the reaction of potassium pyrrolide or 2,5-dimethylpyrrolide with an appropriate chlorophosphine or with POC13 are described. Molecular structures were inferred from spectroscopic data. The P-N bonded phosphines are stable to solvolytic attack by water or alcohols and do not undergo insertion reactions with CS2, but they are oxidised by oxygen and suffer nucleophilic displacement of the azole moiety by strong base. The Lewis acid BC13 cleaves the P-N bond and CH31 reacts with only one member, +2P(py), to form a phosphonium salt. Hindered rotation about the P-N bond was detected in the (2,5-dimethylpyrroly1)phosphine series, but not among the corresponding oxy derivatives. The nature of the P-N bond and trends in the basicity of the phosphorus atom are discussed. On d k r i t les syntheses de pyrrolyl et de dimethyl-2,5 pyrrolyl phosphines +,P(P~)~-, et +,P(Me2py)3-, (x = 0-2) contenant des liens P-N et des derives oxy py3P0 et (Me2py)2P(0)C1 par la rhction du pyrrolure de potassium ou du dimethyl-2,5 pyrrolure de potassium avec une chlorophosphine approprike ou avec POC13. On a propose les structures molCculaires ii partir des donn6es spectroscopiques. Les phosphines contenant un lien P-N sont stables aux attaques solvolytiques de I'eau ou des alcools et ne subissent pas de reactions d'insertion avec le CS2; ils sont toutefois oxydees par l'oxygkne et subissent des ddplacements nuclCophiles de la portion azole sous I'influence de bases fortes. L'acide de Lewis BC13 coupe le lien P-N et le CH31 r h g i t uniquement avec le +2P(py) conduisent ii un sel de phosphonium. On a detect6 un empechement ii la rotation autours du lien P-N dans la serie dimethyl-2,5 pyrrolyl phosphine; ce n'est toutefois pas le cas dans les derives oxy correspondants. On discute de la nature du lien P-N et des tendances dans la basicit6 de I'atome de phosphore.[Traduit par le journal] Introduction The N-pyrrolylphosphines and phosphine oxides are members of the azole phosphine class of compounds, where a heteroaromatic system is bonded via nitrogen to phosphorus (1). Modifications of the chemistry of the P-N bond and of the coordination properties of the phosphorus centre, as compared to dialkylaminophosphine and tris(ary1)phosphine systems, may be expected. In this paper the syntheses and reactions of pyrrolylphosphines are described. A study of metal coordination complexes will be reported later.

N → C2 → C3 migration of the dichlorophosphino group in the synthesis of phosphorylated NH‐pyrroles

“…For unequivocal structural determination of products 2-4, they were converted to stable phosphorus(V) compounds 6a,b, 7a,b, 9-12, and phosphonium salt 13. The phosphorus atom position in products 5, 6a,b, 7a,b, and 8-13 was firmly established by 1 …”

“…Some evidence was reported for the reactions of potassium pyrrolide [1] and pyrrole in the presence of a base [2] with chlorophosphines, involving a pyrrole nitrogen atom, N-pyrrolylmagnesium bromide with phosphorus halides affording C 2 -phosphorylated derivatives…”

Syntheses and properties of phosphino- and phosphinatopyrazoles

“…From lH nmr and mass spectroscopic evidence, the P-N bond in pyrazolylphosphines is rapidly cleaved by BC4, giving products consistent with [4] and [ 5 ] : similar (pyrazoly1)chloroborane derivatives were observed in the mass spectra of the products obtained by treating BC13 with K+pz-.…”

Rhodium Pyrrolylphosphine Complexes as Highly Active and Selective Catalysts for Propene Hydroformylation: The Effect of Water and Aldehyde on the Reaction Regioselectivity

“…In this context, N ‐pyrrolylphosphines should be mentioned. They are strong π‐acceptors, stronger than phosphites (P(OR) 3 ), and, advantageously, the P−N bond is more stable than the P−O bond …”