Ein beitrag zur isocyanatbildung bei der photolyse von acylaziden

Photochemistry of Azides: The Azide/Nitrene Interface

“…117,118 Similar results were obtained for 2 -naphthoyl azide ( 35 ). 122 Irradiation of 35 in cyclohexane at room temperature produces isocyanate (36 , ∼ 45%), N -cyclohexyl -2 -naphthamide -the product of 2 -naphthoylnitrene ( 37 ) insertion ( ∼ 50%), and a trace ( < 1%) of 2 -naphthamide ( 38 ).…”

“…108 -110,119 -133 It has been shown that the yield of isocyanates, formed upon photolysis of a series of carbonyl azides (R -CO -N 3 , R = t -Butyl, Aryl), remains constant in the presence and in the absence of nitrene traps. 111,112,117,118 For example, the yield of isocyanate 33a produced on photolysis of pivaloyl azide (R = tr -Butyl, 31a ) in methylene chloride (an inert solvent) is 40%. Photolysis of 31a in cyclohexene leads to a 45% yield of aziridine adduct 34a and a 41% yield of isocyanate 33a .…”

Ground state multiplicity of acylnitrenes: computational and experimental studies

“…3-8 Therefore, it was concluded that, even if carbonylnitrenes are formed during photoly sis of carbonyl azides, they do not rearrange to isocyan ates. 2, [4][5][6][7] It was demonstrated 9,10 that direct and triplet sensi tized photolysis of benzoyl azide (1) in alkenes produces the same trapping products and that these products are characteristic of reactions of singlet nitrenes. Similar re sults were obtained for 2 naphthoyl azide and a series of substituted benzoyl azides.…”

“…It was deduced that singlet ethoxy carbonylnitrene has a lifetime between 2 and 10 ns in CF 2 ClCFCl 2 at room temperature. 26 In order to understand the proposed difference in the ground state multiplicity of two types of acylnitrenes, RC(O)N and ROC(O)N, we performed high level quan tum chemical calculations of ∆E ST values for two model compounds, formylnitrene HC(O)N (5) and carboxy nitrene HOC(O)N (6). In addition, we calculated barri ers to the reactions of singlet acylnitrenes with ethylene.…”

Jürgen Sauer (1931–2011)

“…Die Freisetzung in 2-Methylbutan führte zur Insertion des Nitrens in die C-H-Bindung mit der Reaktivitätsreihenfolge tert-C-H > sec-C-H > prim-C-H; die Produktverhältnisse waren unabhängig von der Natur des Nitren-Generators, was das Vorliegen einer gemeinsamen Zwischenstufe sichert. [5] Die Oxidation von N-Aminoheterocyclen erbrachte Aminonitrene (RR'N-N), welche mit Styrol als (1þ2)-Cycloaddukte abgefangen wurden. [6] Umsetzungen …”