Dimesitylboryl compounds : V. Aryl, ethenyl, allenyl, phenylethynyl and allyl derivatives☆

摘要: Abstract Trimesitylborane, five aryldimesitylboranes, ethenyl, allenyl, phenylethynyl and allyldimesitylboranes have been synthesised characterised by their 1 H, 11 B 13 C NMR spectra. A set of chemical shift shielding parameters for the dimesitylboryl group obtained which allow assignment resonances in meta -and para -substituted aryldimesitylboranes. On basis data it is concluded that unsaturated ligands stabilise these systems π electron back-donation to empty p orbital on boron order aryl ⪡ allenyl ǎlkenyl ǎlkynyl. Allyldimesitylborane does not undergo expected intramolecular allylic rearrangement solution at temperatures below 140°C.