New P-ligands: The aromaticity and reactivity of 2,4,6-trialkylphenylphospholes

TitleNew P-ligands: The aromaticity and reactivity of 2,4,6-trialkylphenylphospholes
Publication TypeJournal Article
Year of Publication2005
AuthorsKeglevich, G, Farkas, R, Ludányi, K, Kudar, V, Hanusz, M, Simon, K

A further member of 2,4,6-trialkylphenyl-phospholes, the ditertbutylmethylphenyl derivative (1c) was characterized by Bird index and by the sum of angles at the phosphorus atom to describe the flattening of the P-pyramid. Both numbers suggested a slight aromaticity. The reaction of arylphospholes with phosphorus tribromide was extended to phosphole 1c leading this occasion, after further steps, to the mixture of 3- and 2-substituted products (3c-1 and 3c-2, respectively). A triisopropylphenyl-2H-phosphole (4) formed by sigmatropic rearrangement was utilized in the preparation of new 1-phosphanorbornene derivatives, such as sulfide 6 and hemi-oxides 8-1 and 8-2. Further oxidation of the latter species (8-1 and 8-2) led to the decomposition of the dimeric structure (11). 4 could also be trapped by benzaldehyde to afford the oxaphosphanorbomene (10) as one diastereomer. Finally, the reversible formation of 2Hphosphole 4 from 1H-phosphole la at 150 degrees C was proved. (c) 2005 Wiley Periodicals, Inc. Heteroatom Chem.