The synthesis of previously unknown 3,3-diazidooxindoles as synthetically useful derivatives of isatins was accomplished through the direct oxidative diazidation of 2-oxindoles. The method yielded the diazido compounds from the starting oxindoles under mild and simple conditions with NaN 3 and iodine, in good yields. The notable reactivity of this new class of compounds toward primary and secondary nucleophilic amines is also described, which gives access to either 4-imino-3,4-dihydroquinazolin-2(1H)-one derivatives or cyanophenylureas.

The degradation of geminal diazides is described. We show that diazido acetates are converted into tetrazoles through the treatment with bases. The reaction of dichloro ketones with azide anions provides acyl azides, through in situ formation of diazido ketones. We present experimental and theoretical evidence that both fragmentations may involve the generation of acyl cyanide intermediates. The controlled degradation of terminal alkynes into amides (by loss of one carbon) or ureas (by loss of two carbons) is also shown.

A new synthetic route toward the tetrazole core is described, which is based on a general fragmentation pattern that was found in a range of compounds featuring geminal diazido units. Through a simple two‐step procedure, the synthesis of structurally diverse target compounds containing a tetrazole, such as tetrazoloquinoxalinones, benzoylaryltetrazoles, tetrazolotriazinones, and tetrazoloazepinones, was easily accomplished, starting from broadly accessible substrates (i.e., oxindoles, diarylethanones, pyrazolones, and phenanthrols). The initial oxidative diazidation reaction with iodine and sodium azide under mild conditions is followed by the thermal fragmentation under microwave irradiation, leading to the tetrazole products. Noteworthy, an experimental solution is presented in which the potentially hazardous diazide intermediates are not isolated and the concentration of crude reaction mixtures containing diazides is not required to achieve the tetrazoles in good yields.

The area of cascade reactions, initiated by the transition metal‐catalyzed activation of π‐systems and coupled with a 1,2‐migration step is of considerable interest in current organic chemistry research. In this article, recent advances in the field are highlighted, focusing on gold as the activating π‐acid. Cascade reactions with 1,2‐shifts of alkyl groups as migrating agents are mainly presented, but also selected 1,2‐aryl migrations and miscellaneous examples are depicted. With the reactions discussed, molecules of high structural complexity become readily accessible. Examples are shown where the reactions were used as the key steps of total synthesis endeavours.

We describe the synthesis and reactivity of a new class of diazidated compounds: the 2,2‐diazido‐1,2‐diarylethanones. The diazides are easily accessible from 1,2‐diarylethanones through a mild and simple protocol for the direct oxidative diazidation, using iodine and sodium azide in DMSO at room temperature. In studies towards their reactivity with amine nucleophiles under basic conditions, the diazides are shown to undergo a controlled fragmentation reaction that provides a straightforward access to the corresponding amides. In stark contrast to our previous results on the amine‐triggered fragmentation of diazidated compounds, aromatic nitriles are found to be by‐products of synthetic value. The net reaction consisting of diazidation and subsequent fragmentation, thus, provides a simple way to convert 1,2‐diarylethanones into both aromatic amides and nitriles.