Resonance des Phospholes—Reaction Avec le n‐Butyl Lithium

Abstract

Seven phospholes were prepared by a two-step synthesis as previously described. On the basis of H and NMR data, these phospholes were tentatively classified by their degree of aromaticity. Two of these were reacted with n-butyl lithium. Nucleophilic attacks were observed on the phosphorus atom and on the double bonds. These facts are explained by enhanced p-n a n d p n -d w conjugations between the phosphorus atom and the dienic system by comparison with vinyl phosphines. NMR data seem to support this view. The influence on 8 31P of substitution and cyclic delocalization of the lone pair of electrons on phosphorus is interpreted within the Letcher-Van Wazer formalism.

Intra- and intermolecular equilibriums and their pertinence to the mechanism of cis-trans isomerization of L2PtX2 complexes: four- and five-coordinate platinum phosphole complexes

“…Table V. 31 P{' H} and ,9SPt {• H} NMR Spectral Data for L2PtX2 giving rise to the familiar 195Pt "satellites". Hence, one observes a pseudotriplet with relative intensities of 1:4:1 in the 31P{1H| NMR of either isomer with Vptp being the separation of the two outer lines of the pseudotriplet.…”

“…For each of the chloride, bromide, and iodide series of L2PtX2 complexes, a linear relationship is exhibited between the coordination chemical shift, (31 ), and the free-ligand chemical shift, 6(31PUgand), of the form (31 ) = [ (31 )]…”

Phosphole-based ligands in catalysis

“…For example, nucleophilic attacks at phosphorus could be performed with n-BuLi and t-BuLi on DMPP to replace the phenyl P-substituent and afford nBDMP 30 and tBDMP in moderate to high yield (Scheme 6). 31 Nucleophilic substitution reactions may also be performed on 1-cyanophospholes due to their ease of handling, relative air-stability (contrary to 1-halogenophospholes) and good reactivity towards various nucleophilic reagents such as alkoxides and amides. A series of chiral pyrrolidino-phosphole ligands L2 was prepared via a coupling reaction between cyano phosphole derivatives and methoxymethylpyrrolidino amides in situ formed (Scheme 7).…”

Hydrolyse des sels de phospholium monomères: Préparation et propriétés des oxydes de 1,3-diénylphosphines

“…Les phospholes de depart ont etC obtenus par les mkthodes decr~tes dans la litterature (12)(13)(14). La double dtbron~hydratatlon par le DBU donne des produ~ts de purete satisfa~sante dans le cas du trimethyl-1,3,4-phosphole Coi~~pose 4f-rendement 70%; ir (KBr) v: (C=C) 1623; (P=O) 1208 cm-'; rmn 'H (CDCI,, 60 MHz, TMS externe) 6: CH3: 1.96; P-CH2: 2.70 (JH-p = 12 HZ); PCH2Ph: 3.26 (JH-p = 15 HZ); C=CH2: 5.03, 5.16; P-CH: 5.96 (JH-p = 21 Hz); C6H5: 7.15 ppm.…”