A novel and facile synthesis of visible photoluminescence Si nanocrystals by room temperature mechanochemical disproportionation of SiO.

Visible photoluminescence Si nanocrystals (Si NCs) are synthesized via a novel and facile room temperature mechanochemical disproportionation of SiO.

Tandem insertion-cyclization reaction of isocyanides in the synthesis of 1,4-diaryl-1H-imidazoles: presence of N-arylformimidate intermediate.

A straightforward and high-yielding synthesis of 1,4-diaryl-1H-imidazoles is reported. 1,4-Diaryl-1H-imidazoles have been difficult to access in ambient conditions, but our method utilizes two different facets of isocyanide reactivity to achieve it. The reaction is believed to involve (1) NHC-copper-catalyzed isocyanide insertion into alcohol to form an N-arylformimidate intermediate and (2) subsequent base-promoted cycloaddition with benzyl isocyanide derivatives. There is cooperation between these two processes through the deprotonation of benzyl isocyanide by KOtBu. The deprotonation gives tert-butyl alcohol and the benzyl isocyanide anion, which are used for the first and second steps of the reaction, respectively. Various control and kinetic experiments were carried out to gain an in-depth understanding of the reaction mechanism and isocyanide reactivity. The reaction mechanism determined by density functional theory calculations was consistent with the experimental data and provided detailed explanations for the reactivity trends.

Dehydrogenative amide synthesis: azide as a nitrogen source.

A new atom-economical strategy to amide linkage from an azide and alcohol liberating hydrogen and nitrogen was developed with an in situ generated ruthenium catalytic system. The reaction has broad substrate generality including diols for the synthesis of cyclic imides.