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Highly enantioselective hydrogenative desymmetrization of bicyclic imides has been developed with chiral Cp*Ru(PN) catalysts. The present hydrogenation directly provides stereochemically well-defined cyclic compounds with excellent enantiomeric exessses, which might otherwise require a detour to reach.

Incorporation of the heme into globin induces a prominent circular dichroism (CD) band in the Soret region. The appearance of heme optical activity is widely believed to arise from the interaction between the heme and aromatic residues of the globin. However, hemoglobin (Hb) containing the reversed heme exhibits a CD spectrum obviously different from that of native Hb, indicating that the interactions of heme side chains with globin contribute to the appearance of heme optical activity. We examined this possibility by comparing CD spectra of native myoglobin (Mb) and those of Mb reconstituted with synthetic hemes lacking vinyl and/or propionate. Replacement of 2,4-vinyl groups with methyl induced moderate changes. In contrast, replacement of 6,7-propionate groups with carboxylate resulted in complete disappearance of the positive Soret CD band. To get theoretical basis for the contributions of 6,7-side chains on the band, we investigated the CD spectra at a time-dependent density functional theory level. In the antiparallel conformation of the 6,7-side chains, the rotational strengths were calculated to be positive, on the other hand in the parallel conformation to be negative. We also found that the weak Soret CD band in 2,4-dimethyl-6,7-dicarboxyheme can be explained by canceling between different carboxyl conformers.

A Variety of protic 2-(tertiary phosphino)-1-amines (R 2 PCH 2 CHR′NHR′′, P-NH) haVe been prepared from 2-oxazolidinones and secondary phosphines using a newly deVeloped acid-promoted decarboxylatiVe C-P bond formation reaction. Treatment of the resulting chiral P-NH compounds with Cp*RuCl(isoprene) in CH 2 Cl 2 smoothly furnished chiral Cp*RuCl(P-NH) complexes with a typical three-legged pianostool structure, which proVe to be excellent catalyst precursors for asymmetric reactions, including the isomerization of allylic alcohols and hydrogenation of imides.

Awakening of the Cp one: The bifunctional complex 1 facilitates the interaction with substrates bearing less electrophilic carbon atoms than ketones, epoxides, and imides. The title reaction was applicable to the reduction of Evans' asymmetric alkylation products to the chiral alcohols along with good recovery of the chiral oxazolidinone auxiliary. EWG = electron-withdrawing group.