82313-80-2Relevant academic research and scientific papers
Triarylmethyl Systems, IV. Synthesis and Reactions of α-Hydroxy- and α-Halo-α-arylparacyclophanes
Staab, Heinz A.,Kuo-chen, Chi,Ruland, Alfred
, p. 1765 - 1774 (2007/10/02)
By bromination of hydrocarbons 1a - d and 6 α-bromo-α-arylparacyclophanes with n = 5-8 (2a - d, 7) were prepared.Via 2a - d α-hydroxy-α-arylparacyclophanes 3a - d were obtained, starting from which the α-chloro and α-fluoro derivatives 4a - d and 5a,b, resp., were synthesized. - Compounds of the types 2 - 5 were of interest as representatives of a special triarylmethyl system for which, due to the paracyclophane structure, unusual steric and electronic effects were to be expected.The formation of p,p'-bridged triarylmethyl radicals 8 from 2a - d and their dimerisation were investigated.Rate constants for the hydrolysis of α-bromo and α-chloro compounds 2a - d and 4a - d proceeding via the carbenium ions 9 were determined in water/acetone by conductivity measurements.Stabilities of 9 (n = 5-8), formed from the hydroxy compounds 3a - d in conc. sulfuric acid, were determined; their dependence on n is discussed in terms of specific steric and electronic effects of the α-arylparacyclophane system.Some spectroscopic data are reported for the carbanions 10.
