Melting points are corrected. NMR. spectra werc taken on a 100 MHz V a r i a n HA-100, 1H. spectra on a Jasco 1R.-S, UV. spectra on a Beckmanx DK-2A and Mass spectra on a Hitachi RMU-6 spectrometer. Kinetic experiments wcre carried out as described in our former publication Preparation of the mixed double adduct 5 b of 6,6-dimethylfulvene, tropone and 2-chlorotropone. (1 mmol) 2-chlorotropone and138 mg (1.3 mmol) 6,6-dimethylfulvene were kept in a scaled tube under nitrogen at 50'. After 3 days IR. spectroscopy indicated only traces of left 2-chlorotropone. Excess of fulvenc was removed carefully at high vacuum and the remaining material was kept with 318 mg (3 mmol) tropone under nitrogen at 50" for 3 days. Separation by preparative thin layer chromatography (benzenc/methylisopropylketone 9 : 1) yielded 146 mg (42% based on 2-chlorotropone) of mixed double adduct 5b which easily crystallized. Recrystallisation from hot methanol yielded pure material m.p. 161-162". UV. (cyclohexane) : A , , , 203 nm ( F = 11000), 260 nm ( E = 3800), 270 nm (E = 2900).
140.5 mg
IR. (CHC1,) : 1715 (saturated C-0), 1675 cm-l (C=CCl-C-0). Massspectrum: 352 (&I+) 246 (Cl,H,,C1O), 107,106 (C,H,O). The NMR. spectrum in C,D, is very similar to that of compound 5a [2]. The ClC=CH rcsonance appears as one doublet ( J = 9.5) however.