The Radiation-induced Radical Addition Reaction of Aldehydes to 1, 3, 3, 4, 4-Pentafluorocyclobutene

Abstract

The -radiation-induced radical addition reactions of several aldehydes, CH3CHO, C2H5CHO, n-C3H7CHO and i-C3H7CHO to 1, 3, 3, 4, 4-pentaflorocyclobutene (1) were studied.
In the addition of aldehydes to (1), the acyl radical attacked both the =CF side and =CH side of the unsymmectrical double bond, yielding the two isomers, (CF2)2CH2CFCOR (4) and (CF2)2CHFCHCOR (5).The unsaturated 1:1 adduct, (CF2)2CH=CCOR (6) and the 1:2 adduct, ROCCH(CF2)2CHCOR(7) were also produced along with the 1:1 adducts.
The 1:1 adducts, (4) and (5) were obtained in a ratio of 1:2 independent of the structure of the aldehydes.
Although the adduct (5) was dehydrofluorinated upon standing at room temperature to yield the unsaturated adduct (6), the adduct (4) remained unchanged under the same condition.
The order in apparent reactivity of aldehydes observed in the addition reaction was as follows: