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Summary Peter Griess synthesized the first diazo compounds in 1858. August Kekulé played a key role in the elucidation of the structure of this new class of compounds. Around 1886, the photosensitivity of diazo compounds was discovered. This was used to develop the diazotype, a silver‐free copying process which produces azo dyes. Finally, a suggestion is made on how the diazotype can be implemented in chemistry classes. [ABSTRACT FROM AUTHOR]

A high-yielding method for the synthesis of 2 H -1,3,5-oxadiazines by rhodium(II)- or copper(II)-catalyzed reaction of 1,2,4-oxadiazoles with α-diazo esters has been developed. The reaction proceeds via attack of the metallocarbenoid on the oxadiazole N2 atom followed by ring opening/1,6-electrocyclization and enables the introduction of alkyl, aryl, oxy, and amino substituents into the 6-position and electron-withdrawing groups into the 2-position of 1,3,5-oxadiazine. The N2-attack and the N4-attack of the carbenoid cause different oxadiazole ring openings, which are controlled by the substitution at C5. The presence of a substituent at this position is a prerequisite for the N2-attack to occur, leading to the formation of 1,3,5-oxadiazines. [ABSTRACT FROM AUTHOR]

A simple synthetic procedure for the Pd-catalyzed hydro-arylation of diazoacetic ester has been previously developed in our laboratory. Now we have applied this methodology for hydroarylation of α-diazocarboxylates/α-diazophosphonates. Diazo compounds reacted with aryl iodides and formic acid to afford diarylated esters or phosphonates in yields up to 71%. [ABSTRACT FROM AUTHOR]

Using ?-diazo-?-ketoesters as reagents and combinations of CpRu fragments and diimine ligands as catalysts, a series of original transformations have been obtained that can be rationalized by the formation of metal carbenes and metal-bound ylide intermediates. Interesting 1,3-dioxole, enol-acetal and 1,4-dioxene motifs are obtained directly when the reactive mixture is reacted in presence of aldehydes or ketones, THF and epoxides.