The development of synthetic methods for monodisperse nanomaterial is of great importance in science and technology related to nanomaterials. The strong demands to prepare exceptionally monodisperse nanocrystals have made digestive-ripening one of the most sought-after size-focusing processes. Although digestive-ripening processes have been demonstrated to produce various metals and semiconductors, their applicability to oxides has rarely been studied despite various unique properties and applications of oxide nanomaterials. In this work, we demonstrate the successful synthesis of monodisperse V-doped In 2 O 3 nanocrystals via a modified digestive-ripening process. The nanocrystals have truncated octahedral shape faceted with eight (222) and six (220) planes. To the best of our knowledge, this is the first report on the digestive-ripening synthesis of highly symmetrical doped oxide nanocrystals. Moreover, Vdoped In 2 O 3 nanocrystals exhibit electrocatalytic activities for CO 2 electrochemical reduction and produce CH 3 OH, which has not been attainable from previously reported electrocatalysts based on indium or indium oxide. This distinctive catalytic property of Vdoped In 2 O 3 is attributed to the presence of V-dopants in the In 2 O 3 host. Our demonstration has important implications for both nanocrystal synthesis and electrocatalyst development.

The chemistry of hydrogen cyanide adducts of imines is well-developed, but that of cyanide adducts remains unexplored. This is presumably because these cyanide adducts are not stable and thus not readily available in their isolated forms. In this personal account, we present the progress made in our research program towards the development of novel organic transformations utilizing cyanide adducts of imines as key intermediates. We also report the application of these methodologies to the total synthesis of natural products including indole alkaloids.

A new strategy applicable to the synthesis of indoloquinolizine natural products has been developed. A cyanide-catalyzed intramolecular imino-Stetter reaction of aldimines, derived from 2-aminocinnamic acid derivatives and 2-pyridinecarboxaldehydes, provided indole-3-acetic acid derivatives bearing a pyridyl ring at the 2-position. Reduction of the carboxylic acid moiety to an alcohol followed by activation of the resulting alcohol with TfO or TsCl generated indoloquinolizinium salts, which were utilized as precursors for indoloquinolizine natural products. The advantage of this protocol was successfully demonstrated in the total syntheses of arborescidine A and nauclefidine.

Electrocatalysts for C3 chemicals, such as acetone in CO2 reduction reaction, are predominantly limited to Cu-based materials. Therefore, it is highly desirable to devise design strategies and synthetic routes for novel electrocatalysts. This study demonstrates an original synthetic route toward uniform crystalline/amorphous Ni2P/Ho2O3 core/shell nanoparticles (CSNPs), which produce acetone with a Faradaic efficiency of 25.4%. To date, this is by far the best performance demonstrated with non-Cu-based electrocatalysts. These excellent CSNP properties can be attributed to their unique heterostructures because Ni2P or Ho2O3 electrocatalysts alone cannot produce acetone. Our demonstration greatly contributes to the development of innovative electrocatalysts, especially for valuable multicarbon (C3+) chemicals.

In operando observation of reaction intermediates is crucial for unraveling reaction mechanisms. To address the sensitivity limitations of commercial ReactIR, a flow cell was integrated with a Fourier transform infrared (FTIR) spectrometer yielding a "flow FTIR" device coupled with an NMR spectrometer for the elucidation of reaction mechanisms. The former device detects the low-intensity IR peaks of reaction intermediates by adjusting the path length of the FTIR sample cell, whereas the flow NMR allows the quantitative analysis of reaction species, thus offsetting the limitations of IR spectroscopy resulting from different absorption coefficients of the normal modes. Using the flow NMR and FTIR device, the controversial mechanism of benzoxazole synthesis was conclusively determined by spectroscopic evaluation of the reaction intermediates. This system enabled the accurate acquisition of previously elusive kinetic data, such as the reaction time and rate-determining step. The implementation of reaction flow cells into NMR and FTIR systems could be widely applied to study various reaction mechanisms, including dangerous and harsh reactions, thus avoiding contact with potentially harmful reaction intermediates.

Concise total syntheses of rac-and (+)-goniomitine were developed. The cyanide-catalyzed imino-Stetter reaction of an aldimine, derived from ethyl 2-aminocinnamate and either rac-or (S)α,β-unsaturated aldehyde bearing a δ-valerolactam at the β-position, provided rac-or (S)-indole-3acetate carrying an α-vinyl-δ-valerolactam scaffold at the 2-position, respectively. Subsequent saturation of the vinyl group, followed by treatment with DIBAL-H, afforded N-benzyl protected goniomitine. Final debenzylation provided the desired natural product after only three column separations.

A general synthetic strategy for antirhine alkaloids was developed in this study. The cyanide-catalyzed imino-Stetter reaction of ethyl 2-aminocinnamate and 4-bromopyridine-2-carboxaldehyde afforded the corresponding indole-3-acetic acid derivative. Subsequent formation of the six-membered C ring followed by trans-selective installation of the two-carbon unit at C-15 provided rapid access to the key intermediate. Stereoselective installation of substituents at C-20 allowed the total syntheses of (±)-antirhine, (±)-18,19-dihydroantirhine, and their 20-epimers, all of the known natural products in the antirhine family.

A different reactivity between cyanide and NHC with 4‐(2‐formylphenoxy) but‐2‐enoate derivatives is described.