For the first time, the title alcohol 3 was unambiguously detected as a transient intermediate leading to ditropylether (6) in a cation–anion reaction between the tropylium ion (5) and hydroxide ion in an aqueous solution by NMR spectroscopy. It was also found that 6 gives 3 as a transient product in acid-catalyzed disproportionation of 6 into a mixture of tropone (4) and 1,3,5-cycloheptatriene (7)
UV-laser photochemistry: Generation of the triplet spiro[2.6]nona-4,7-diyl diradical by nitrogen extrusion from the azoalkane 6,7-diazaspiro[bicyclo (3.2.2)non-6-ene-2,1′-cyclopropane]. Conformational influence on the lifetime of a 1,4-cycloheptadiyl as determined by the cyclopropylcarbinyl “free radical clock”
作者:Waldemar Adam、Sven Grabowski、Frank Scherhag
DOI:10.1016/s0040-4039(00)80832-1
日期:1988.1
Using the cyclopropylcarbinyl rearrangement, the lifetime of the tripletdiradical spiro[2.6]nona-4,7-diyl was estimated as 0.3 < 3τ < 3.3 ns; the short tripletlifetime of this localized 1,4-diradical is rationalized in terms of fast ISC out of its initial boat or twistboat conformation.