The polarity-mismatched perfluoroalkyl radical addition to electron-deficient alkenes was studied. For this study, several substrates having two polarity-different radical acceptors were employed to investigate the regiochemical courses of cascade reaction. In the case of substrate 1 having a methacryloyl moiety, we found polarity-mismatched perfluoroalkylation giving 15a-e as a major course over the polarity-matched perfluoroalkylation giving 16a-e. Moreover, in the case of substrates 2-7, perfluoroalkyl radicals selectively added to an electron-deficient alkene moiety of 2-7, to give polarity-mismatched perfluoroalkylation products without the formation of regioisomers. Next, the control of enantioselectivity was studied. In the case of substrates 1 and 3, the reaction proceeded with good enantioselectivities by employing a chiral Lewis acid, prepared from chiral box ligand 24 and Zn(OTf)(2). For direct comparison, we also studied the reaction with other carbon radicals, derived from ICH(2)CO(2)Et, ICH(2)CN, BrC(CO(2)Et)(2)Me, and CCl(3)Br, which have electrophilic character.

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The ruthenium photocatalyst Ru(bpy) 3 Cl 2 •6H 2 O has the potential to catalyze the cascade radical reaction with perfluoroalkyl radicals in aqueous media via two photoredox cycles.

Stereoselective construction of aza-quaternary carbon centers was achieved using the alkylation of oxathiazinane N,O-ketals prepared by Rh(II)-catalyzed C-H amination of sulfamates. The addition of alkyl Grignard reagents into N,O-ketals in the absence of any Lewis acid proceeded stereoselectively to provide the corresponding alkylated products with an aza-quaternary carbon center in high yields. The obtained product could be converted into an α-amino alcohol derivative, which is a potential synthetic intermediate for sphingofungin F and its derivatives.

Photocatalytic Cascade Carbon-Carbon Bond-Forming Radical Reaction in Aqueous Media. -A Ru-catalyzed photolytic cascade radical reaction of dienic derivatives of O-benzyl hydroxylamine with perhalogenated aliphatic halides is developed leading to functionalized pyrrolidinones as mixtures of diastereomers, also for compounds (III), or as mixtures of E/Z isomers. -(YOSHIOKA, E.; KOHTANI*, S.; TANAKA, E.; MIYABE, H.; Synlett 24 (2013) 12, 1578-1582, http://dx.doi.org/10.1055/s-0033-1339182 ; Sch. Pharm., Hyogo Univ. Health Sci., Kobe 650, Japan; Eng.) -Mais 46-107