Kinetics and mechanism of the protonation of 6-(triphenylphosphonio-3?-cyclopentadienyl)-2,3,5-trihalocyclohexa-2,5-diene-1,4-dione by trifluoroacetic acid in aprotic media

Cationic Terminal Borylene Complexes: Structure/Bonding Analysis and [4+1] Cycloaddition Reactivity of a BN Vinylidene Analogue

“…Spectroscopic data for single crystals redissolved in CD 2 Cl 2 imply the presence of a second species, which is thought to be an alternative isomer featuring the methylene group in the 4‐position. The existence in solution of disubstituted cyclopentadienes of the type 1,3‐(Ph 3 P)(X)C 5 H 4 as a mixture of isomers has previously been demonstrated 16…”