2,2‐Diazido‐1,2‐diarylethanones: Synthesis and Reactivity with Primary Amines

Abstract

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.

Ring Expansion of 2-Azido-2-phenyl-indan-1,3-dione for the Generation of Heterocyclic Scaffolds

“…26 In the course of our recent studies on the reactivity of geminal diazides, 27−29 we then stumbled upon a report by Bruvele on how the azide 1a undergoes ring-opening when treated with amines in 1,4dioxane at room temperature; imine 3 was described to become the product of this carbon−carbon bond cleavage reaction (Scheme 1b). 30 Because this result is well-matched with our own findings that nucleophilic amines are capable of provoking the fragmentation of certain 2-azido carbonyl systems, 31 we sought to use 2-azido-1,3-indandiones of type 1 for the new and general route toward 3-amino-2,3dihydroisoquinoline-1,4-diones 6 outlined in Scheme 1. It was expected that the ring-opening of the azide 1 is initiated by the nucleophilic attack of the amine, and the resulting anion then decomposes with loss of dinitrogen, forming the Bruvele imine, which finally cyclizes by an intramolecular attack that results in a net ring expansion.…”

A Synthetic Route Toward Tetrazoles: The Thermolysis of Geminal Diazides

“…Next, we sought to expand the tetrazole‐forming method to other classes of easily accessible diazides. To our delight, the conversion of diazidodiarylethanones 11 a and 11 b furnished the corresponding benzoylaryltetrazoles 12 , under the straightforward thermolysis conditions, after a slightly elongated reaction time (Scheme ). The yields were excellent, and the 5‐aroyl‐1‐aryltetrazoles were the only products obtained, whereas the isomeric 1‐aroyl‐5‐aryltetrazoles were not formed.…”

“…The method was further extended to the aromatic core of 9‐phenanthrol ( 14 ) (Scheme ). The diazidation conditions led to the formation of diazidocarbonyl compound 15 in 77 % yield, and the aromaticity of the central ring was abolished. Under microwave irradiation at 140 °C, fragmentation of the diazido unit occurred, providing the 9 H ‐dibenzo[ d , f ]‐tetrazolo[1,5‐ a ]azepin‐9‐one ( 16 ) in 91 % yield.…”

Reactivity of Organic Geminal Diazides at Tetrahedral Carbons

“…For example, various 2,2‐diazido‐1,2‐diarylethanones 57 were efficiently converted with benzylamine yielding the expected amides 58 in combination with the nitriles 59 . [ 58 ] Cesium carbonate (1.0 equiv.) was added as an additive and the reaction was run in DMF at room temperature for 24 h (Table 2).…”