Phospha‐Michael‐Type Reactions between 1,2‐Diaza‐1,3‐dienes and Bidentate Nucleophiles: Formation of New Mono‐ and Diylides and their Elaboration to Heterocycles

Abstract

Phospha‐Michael additions of a series of methylene‐bridged phosphorus bidentate nucleophiles to 1,2‐diaza‐1,3‐dienes gave monoadducts and bisadducts in high yields under mild conditions. In particular, a series of new ylides and symmetrical diylides have been obtained from bis(diphenyl)phosphanes. The use of diphenylphosphanylamino derivatives gave, through phospha‐Michael addition, ylide intermediates that underwent spontaneous intramolecular attack by the amino group belonging to the Michael donor reagent moiety, thus giving access to new heterocycles.

New electron-donor and -acceptor architectures from benzofurazans and sym-triaminobenzenes: intermediates, products and an unusual nitro group shift

“…In the above reaction, as well as in the Michael-type addition to 1,2-diazabuta-1,3-dienes, 20 and in azo coupling with diazonium salts, [21][22][23] sym-triaminobenzenes 1-3 behave as carbon nucleophiles. On the contrary, with electrophiles such as protons 24,25 and alkyl halides, [26][27][28] they undergo an attack on both the aromatic carbon atom and the nitrogen atom of the amino substituent, to a relative extent, depending on the experimental conditions.…”

“…Dipyrrolidin-1-ylphenyl)-1-(7-nitro-2,1,3-benzoxadiazol-4-yl)pyrrolidinium chloride(20). Brown solid, quantitative yield,1 H NMR (600 MHz, CDCl 3 ): δ = 9.07 (d, 1H, J = 7.5 Hz), 8.56 (d, 1H, J = 7.5 Hz), 6.39 (s, 1H), 5.40-4.80 (m, 2H), 4.92 (s, 2H), 3.70-3.67 (m, 2H), 3.67-3.60 (m, 2H), 3.60-2.40 (br, ms, 6H), 2.40-1.50 ppm (m, 12H); 13 C NMR (150.80 MHz, CDCl 3 ): δ = 160.8, 157.2, 148.3, 143.1, 136.4, 134.9 (CH), 130.8, 130.4 (CH), 86.4 (CH), 50.0 (CH 2 ), 49.1 (CH 2 ), 45.5 (CH), 25.0 (br, CH 2 ), 24.9 ppm (CH 2 ).…”