Methylene cycloheptanone

The generation of homo- and copolymers prepared by Friedel-Crafts reactions of 2,7-bis [(2-ferroceneyl)methylene]cycloheptanone with various diacid chlorides has been reported.222 These polyketones were insoluble in most common organic solvents, but were quite soluble in concentrated H2S04. The homopolymers were thermally stable with two decompositions between 220 and 520°C, and the copolyketones showed decomposition at temperatures between 250 and 600°C. In both cases the first weight loss was determined to depend on the nature of the polymers and occurred at a faster rate than the second degradation. 

Photochemical Reactions. Photolysis of (49) gives a low yield of 4-methylene-cycloheptanone and photolysis of (50a) and its cis-isomer in the presence of a reducing solvent gives (50b) the mechanism of the latter reaction has been studied by deuterium-labelling. The reducing solvent is needed even though a net reduction has not occurred. 

When Br is substituted for I, the cyclohexanone product can be isolated in predominance only when HMPT is the solvent. If the methylene chain is lenghened by one unit, the cyanohexane and unreacted starting material are the major products. Only 2% of a cycloheptanone is isolated. 

Ahyd// was measured in acetic acid and corrected for Aso // of tropone in acetic acid using Pd on BaS04 catalyst. The reaction product was cycloheptanone. The resonance stabilization by the carbonyl group is only slightly less than that of the methylene group in heptafulvene. Compare tropylidene and heptafulvene. 

Dichloroketene can be reacted with N,N-disubstituted 2-aminomethy-lene-cyclopentanones 101a, -cyclohexanones 101b, -cycloheptanones 101c, and -cyclooctanones lOld to afford the 1,4-cycloaddition products, N,N-disubstituted 3,3-dichloro-4-amino-5,6-poly-methylene-3,4-dihydro-u-pyrones 102 (Scheme 34) (1972JHC1071). Diphenylketene and ketene also can undergo this 1,4-cycloaddition reaction (1967MFC1518). 

Cycloheptanone allowed to react with dilorotrimethylsilane in dimethylformamide in the presence of triethylamine enoxysilane deriv. (Y 90%) allowed to react with 1.5 equivalents zinc-silver couple and methylene iodide, then with pyridine siloxycyclopropane deriv. (Y 75%)... 

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