A general synthetic methodology toward the erythrina alkaloids has been developed. Inspired by a proposed biosynthetic mechanism, the medium-sized chiral biaryl lactam was asymmetrically transformed into the common core A–D rings by a stereospecific singlet oxygen oxidation of the phenol moiety, followed by a transannular aza-Michael reaction to the dienone functionality. The late-stage manipulation of the oxidation and oxygenation states of the functional groups on the peripheral moieties enabled the flexible syntheses of the erythrina alkaloids.

A general synthetic methodology toward the erythrina alkaloids has been developed. Inspired by a proposed biosynthetic mechanism, the medium-sized chiral biaryl lactam was asymmetrically transformed into the common core A–D rings by a stereospecific singlet oxygen oxidation of the phenol moiety, followed by a transannular aza-Michael reaction to the dienone functionality. The late-stage manipulation of the oxidation and oxygenation states of the functional groups on the peripheral moieties enabled the flexible syntheses of the erythrina alkaloids.

A new Co complex of a unique diamidine ligand catalyzes asymmetric NaBH₄ reduction of C3-disubstituted (E)- and (Z)-2-propenoates, including C3-oxygen- and nitrogen-substituted substrates with high enantioselectivity. Analysis by X-ray diffraction, ¹H NMR spectroscopy, ring-opening radical-clock and D-labeling reactions, and the structure/selectivity relationship suggest that a mechanism of CoH-involved non-single-electron transfer 1,4-addition differentiates the C2 enantioface. Involvement of CoH species has been supported by quantitative isolation of a new type of CoH₂(BH₃)₂ complex.

A sulfonamide-based protecting group (PG), (9H-fluoren-9-yl)methanesulfonyl (Fms), which can be used in a similar way to the well-established Fmoc PG, was developed. The advantages of this new PG were demonstrated in the successful formation of a phosphonamide between an N-Fms-protected α-phosphonoalanine monoester and secondary alkylamines, including (R)-2-phenylethylamine, (S)-phenylalanine tert-butyl ester (H-Phe-OtBu), H-Pro-Gly-OtBu, and H-Phe-Phe-OtBu, without formation of oxazaphospholine, which is a serious problem associated with the Fmoc PG. The success should pave the way to the solid-phase synthesis of unnatural peptides substituted with α-amino phosphonic acid (AP) at essentially any arbitrary position without significant modification of the Fmoc-based chemistry that has been accumulated since Carpino's report in 1970. The N-Fms-AP monomer would attract much attention in the field of peptide mimetics.

The highly reactive and chemoselective homogeneousdeallylation catalyst CpRu(η³-C₃H₅)(4-substituted-2-pyridinecarboxylato) was immobilized on microsize spherical Fe₃O₄@SiO₂ particles. The resultant heterogeneous catalyst displays high saturation magnetization, weak coercive forces and high levels of dispersibility. The catalyst has increased the utility of deallylation by allowing the reaction to be conducted without extra additives. The only co-product of the reaction is a volatile allyl ether compound. Here, we demonstrate the efficient deallylation and separation of highly polar multifunctional compounds as well as multiple rounds of catalyst recycling without significant loss of reactivity. The usefulness of this catalyst has been confirmed by the synthesis of a triribonucleotide 3–5 U. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Establishment of a highly reliable and safe procedure for the preparation of TlBH₄ has led to, for the first time, a simple approach to TlTp-related complexes, which are known as mild and efficient Tp-transfer reagents to a variety of metals. The practical use of this method has been demonstrated by the efficient synthesis of (S,S,S)-TlTp^4Bo3MeCpenta from a new and hard-to-obtain chiral pyrazole (HPz). In view of the importance of the scorpionates, this new method should attract the attention of researchers in a wide range of scientific and technological fields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)