Enantioselective decarboxylative alkylation reactions: catalyst development, substrate scope, and mechanistic studies.

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 precursor: enol carbonates, enol silanes, and racemic ß-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.

Regioselective synthesis of 1,4-di(organo)[60]fullerenes through DMF-assisted monoaddition of silylmethyl Grignard reagents and subsequent alkylation reaction.

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.

Synthesis of imino[60]fullerenes using nitriles and trimethylsilylmethyl triflate.

The synthesis of a new class of fullerene derivatives, 1-imino-4-silylmethyl[60]fullerene derivatives, is described. The anion (C(60)R(1-)) of an alkyl- or aryl-adduct of [60]fullerene, C(60)R(1)H (R(1) = CH(2)SiMe(3), CH(2)SiMe(2)Ph, C(6)H(4)-OMe-4, C(6)H(4)-NMe(2)-4, C(6)H(4)-CF(3)-4 and C(6)H(4)-OMe-2), was allowed to react with a nitrilium salt [R(2)CNCH(2)SiMe(3)][OTf] (Tf = SO(2)CF(3)) that was generated in situ by the reaction of Me(3)SiCH(2)OTf and a nitrile solvent R(1)CN (R(2) = Ph and Me). The desired imino[60]fullerene derivative C(60)(R(1)) [C(=NCH(2)SiMe(3))R(2)] was produced in a yield up to 80%. The structure of the product with R(1) = C(6)H(4)-OMe-4 and R(2) = Ph was determined by single-crystal X-ray analysis.