Cyclobutanone alkanone

In spite of the overall similarity of the fluorescence emission of cyclobutanone to other cyclic alkanones in the vapor phase (broad emission maximum near 400 nm), Hemminger, Rusbult, and Lee (17) report that the solution fluorescence emission of cyclobutanone is exceptional in two important ways (a) (excitation near 310 nm in cyclohexane) is about 1 x 10-4, or nearly 1/20th of the vapor-phase value, and (b) the fluorescence... 

We shall see that a discussion of the photochemistry of cyclobutanones in solution will help unravel the nature of the rapid new process which makes of cyclobutanones so much more reactive than other alkanones. The inherent ring strain of cyclobutanone probably triggers the pre-dissociative behavior of the molecule in the state. 

Finally let us consider the very unusual bimolecular addition of dienes to cyclobutanones (34), a flagrant violation of Rule 7. The reactions which were run at -78 °C can be understood if we assume that the rate of cleavage of to a biradical is slowed down because of a decrease in the available thermal activation. However, a moderate yield of oxetane is formed from cyclobutanone and butadiene (19) at 10°C. From work on the quenching of fluorescence by alkanones (53), we anticipate the rate of... 

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