A sequential diversification approach for the synthesis of various multi-substituted β-keto amide derivatives based on a simple and readily available dioxinone scaffold was developed. The process involves: (1) nucleophilic addition of the scaffold to an aldehyde, and a subsequent one-pot dehydration; (2) palladium-catalysed cross-coupling of the scaffold with either an arylboronic acid pinacol ester, or CO and an aliphatic amine; and (3) nucleophilic addition of either an aliphatic amine or an arylamine, or a hetero-Diels–Alder reaction of isocyanate/isothiocyanate, with an acylketene generated in situ from the dioxinone scaffold.

The development of highly efficient amide bond forming methods which are devoid of side reactions, including epimerization, is important, and such a method is described herein and is based on the concept of rapid and strong activation of carboxylic acids. Various carboxylic acids are rapidly (0.5 s) converted into highly active species, derived from the inexpensive and less-toxic solid triphosgene, and then rapidly (4.3 s) reacted with various amines to afford the desired peptides in high yields (74 %–quant.) without significant epimerization (≤3 %). Our process can be carried out at ambient temperature, and only CO₂ and HCl salts of diisopropylethyl amine are generated. In the long history of peptide synthesis, a significant number of active coupling reagents have been abandoned because the highly active electrophilic species generated are usually susceptible to side reactions such as epimerization. The concept presented herein should renew interest in the use of these reagents.

The development of highly efficient amide bond forming methods which are devoid of side reactions, including epimerization, is important, and such a method is described herein and is based on the concept of rapid and strong activation of carboxylic acids. Various carboxylic acids are rapidly (0.5 s) converted into highly active species, derived from the inexpensive and less-toxic solid triphosgene, and then rapidly (4.3 s) reacted with various amines to afford the desired peptides in high yields (74 %–quant.) without significant epimerization (≤3 %). Our process can be carried out at ambient temperature, and only CO₂ and HCl salts of diisopropylethyl amine are generated. In the long history of peptide synthesis, a significant number of active coupling reagents have been abandoned because the highly active electrophilic species generated are usually susceptible to side reactions such as epimerization. The concept presented herein should renew interest in the use of these reagents.

The creation of organic dyes with excellent high power conversion efficiency (PCE) is important for the further improvement of dye-sensitized solar cells. We wish to describe the rapid synthesis of a 112-membered donor-π-acceptor dye library by a one-pot procedure, evaluation of PCEs, and elucidation of structure–property relationships. No obvious correlations between ε, and the η were observed, whereas the HOMO and LUMO levels of the dyes were critical for η. The dyes with a more positive E_HOMO, and with an E_LUMO<−0.80 V, exerted higher PCEs. The proper driving forces were crucial for a high J_sc, and it was the most important parameter for a high η. The above criteria of E_HOMO and E_LUMO should be useful for creating high PCE dyes; nevertheless, that was not sufficient for identifying the best combination of donor, π, and acceptor blocks. Combinatorial synthesis and evaluation was important for identifying the best dye.