No abstract

Monoaddition of Grignard reagents, in particular tri(organo)silylmethylmagnesium chlorides, to [60]fullerene took place smoothly in the presence of dimethylformamide to produce (organo)(hydro)[60]fullerenes, C60R(1)H, in good yield (up to 93% isolated yield). The hydrofullerene was then deprotonated to generate the corresponding anion, C60R(-), which was then alkylated to obtain 58pi-electron di(organo)[60]fullerenes, C60R(1)R(2), in good to high yield (up to 93% overall yield). The two-step methodology provides a wide variety of 1,4-di(organo)[60] fullerenes bearing the same or different organic addends on the [60] fullerene core. By changing the addends, one can control the chemical and physical properties of the compounds at the molecular and bulk levels.

α-Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursors: enol carbonates, enol silanes, and racemic β-ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target-directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner-sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center.