Manganese(III) Mediated Reactions of Unsaturated Systems

Chemistry of β-(Acyloxy)alkyl and β-(Phosphatoxy)alkyl Radicals and Related Species: Radical and Radical Ionic Migrations and Fragmentations of Carbon−Oxygen Bonds

“…3,4 This chemistry is nicely complemented by the manganese triacetate oxidative cyclizations of malonate esters. [5][6][7] Electrophilic radicals cannot be used to generate enolyl ester substituted radicals, however, as they preferentially abstract hydrogen atoms R to ethereal ester oxygens, giving R-carboxylalkyl radicals. This regioselectivity can be reversed when amine-borane catalysts are employed.…”

Manganese(III) acetate mediated synthesis of 3-trifluoroacetyl-4,5-dihydrofurans and 3-(dihydrofuran-2(3H)-ylidene)-1,1,1-trifluoroacetones by free radical cyclization. Part 1

“…It is possible to conclude that compounds 4 form when R 2 is an alkyl. Mn(OAc) 3 mediated treatment mechanisms of 1,3-dicarbonyls, b-ketoesters and carboxylic acids have been given in detail in the literature [16,17]. In Scheme 1, we propose the mechanism of 3-trifluoroacetyl-4,5-dihydrofurans (3a-n) and 3-(dihydrofuran-2(3H)-ylidene)-1,1,1-trifluoroacetones (4a, 4b) reactions.…”

“…Especially, Mn(OAc) 3 is effectively used in the synthesis of furans [10][11][12], dihydrofurans [13][14][15][16], lactones [17], biologically active compounds and natural products [17][18][19][20][21] but up to date this method has not been applied to the Mn(OAc) 3 mediated reaction of the trifluormethyl-1,3-dicarbonyl compounds with alkenes. In this study, we have obtained 3-trifluoroacetyl-4,5-dihydrofuran and 3-(dihydrofuran-2(3H)-ylidene)-1,1,1-trifluoroacetone compounds by Mn(OAc) 3 mediated radical cyclization of 4,4,4-trifluoro-1-thien-2ylbutane-1,3-dione (1a), 4,4,4-trifluoro-1-phenylbutane-1,3-dione (1b), and 1, 1,1-trifluoropentane-2,4-dione (1c) with various conjugated alkenes.…”

Mn(III) acetate mediated diasteroselective [3+2] oxidative addition of 1,3‐dicarbonyl compounds with chalcones

“…The versatility of this technology has encouraged great interest in the development of novel reagents and procedures for the generation of radicals [2]. Ceric ammonium nitrate (CAN) and manganese(III) acetate have been extensively used as single electron transfer agents for the construction of C-C bonds [1][2][3][4]. Furthermore, the utility of CAN in carbonheteroatom bond forming reactions (C-N, C-S, C-Se, CBr, C-I) was demonstrated [5].…”