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The formation of alkylidenezinc carbenoids by 1,4-addition/carbozincation of dialkylzincs or alkyl iodides based on zinc atom radical transfer, in the presence of dimethylzinc with β-(propargyloxy)enoates having pendant iodo- and bromoalkynes, is disclosed. Formation of the carbenoid intermediate is fully stereoselective at −30 °C and arises from a formal anti-selective carbozincation reaction. Upon warming, the zinc carbenoid is stereochemically labile and isomerizes to its more stable form.

A domino 1,4-addition/alkyne carbozincation sequence based on a radical zinc-atom transfer process is disclosed. Two efficient multicomponent approaches to 3-alkylidenetetrahydrofurans from β-(propargyloxy)enoates bearing pendant alkynes (including ynamides) have been established: one involving the direct addition of dialkylzincs, and the second involving the dimethylzinc-mediated addition of alkyl iodides. Both sequences utilize the stereoselective formation of intermediate alkylidenezincs well suited for in situ functionalization with electrophiles. [ABSTRACT FROM AUTHOR]

The first examples of inorganic nitrite complexes of the natural actinides are described, including the structures of the homoleptic thorium(iv) [PPh4]2[Th(NO2)6] and the uranyl(vi) [PPh4]2[UO2(NO2)4] complexes; the nitrite ligand can adopt two different coordination modes in the coordination sphere of the uranyl ion and is unstable towards reduction. [ABSTRACT FROM AUTHOR]