✍ Scribed by Mehmet Yılmaz; E. Vildan Burgaz Yılmaz; A. Tarık Pekel
No coin nor oath required. For personal study only.
Radical cyclizations of fluorinated 1,3‐dicarbonyl compounds with dienes mediated by Mn(OAc)~3~ afforded 4,5‐dihydrofurans containing difluoroacetyl, trifluoroacetyl, or heptafluorobutanoyl groups in good‐to‐excellent yields. Additionally, 2‐(difluoromethyl)‐4,5‐dihydrofurans and a 4,7‐dihydrooxepin derivative were obtained as unexpected products in the reaction of 4,4‐difluoro‐1‐phenylbutane‐1,3‐dione with 1,3‐diphenylbuta‐1,3‐diene. The radical cyclization of symmetrical dienes such as 2,3‐dimethylbuta‐1,3‐diene and 1,4‐diphenylbuta‐1,3‐diene with 1,3‐diketones furnished the corresponding products in low yields. However, treatment of 1‐phenylbuta‐1,3‐diene with 1,3‐dicarbonyl compounds afforded 4,5‐dihydrofurans containing fluoroacyl groups. The radical cyclizations with 3‐methyl‐1‐phenylbuta‐1,3‐diene and 1,3‐diphenylbuta‐1,3‐diene led to 4,5‐dihydrofurans in good yields, since Me and Ph groups at C(3) of these dienes increase the stability of the radical intermediate.
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## Abstract Manganese(III) acetate catalyzed oxidative radical‐addition reactions of __α__‐dicarbonyl compounds such as methyl acetoacetate (**6**), acetylacetone (**7**), and dimedone (**8**) to the mixture of 1‐ and 2‐phenylcyclohepta‐1,3,5‐triene (**4** and **5**) were investigated (__Scheme 1__