Vier- und fünfgliedrige phosphorheterocyclen

Preparation and Reactivity of Some New Diazaphospholine Compounds

“…The reaction comes to completion in 12 days and is accompanied by the formation of significant amounts of by-products and unidentified compounds. Phenyldichlorophosphine and 5-methyl-2furyldichlorophosphine [8] react with cyclohexanone phenylhydrazone under the same conditions in 12 h affording 1,2,3-diazaphospholines 3b in high yields.…”

Electron‐Rich Aromatic 1,3‐Heterophospholes – Recent Syntheses and Impact of High Electron Density at σ2P on the Reactivity

“…For 1‐methyl‐1,2,4‐diazaphosphole ( 2b ), with similar low reactivity in addition reactions, analogous CH‐lithiation takes place with BuLi in the 5‐position 70. 2‐Substituted 1,2,3‐diazaphospholes with a P–N bond, however, prefer addition of t BuLi in pentane or of n BuLi or LDA in THF at the P=C bond 66,70. Use of MeLi in Et 2 O also favors the addition and displays only minor CH‐lithiation in 4‐position of 2,5‐dimethyl‐1,2,3‐diazaphosphole 70.…”

“…2‐Substituted 1,2,3‐diazaphospholes with a P–N bond, however, prefer addition of t BuLi in pentane or of n BuLi or LDA in THF at the P=C bond 66,70. Use of MeLi in Et 2 O also favors the addition and displays only minor CH‐lithiation in 4‐position of 2,5‐dimethyl‐1,2,3‐diazaphosphole 70. The lithiated 1,2,4‐diazaphospholes and 3,4‐dihydro‐1,2,3‐diazaphospholes were coupled with MeI, ClSiMe 3 and chlorostannyl‐3‐diethylboryl‐2‐pentene,70 the 4‐lithio‐3,4‐dihydro‐1,2,3‐diazaphospholes also with CO 2 or protonated (with HCOOH)66 to give the corresponding substitution products.…”

“…Use of MeLi in Et 2 O also favors the addition and displays only minor CH‐lithiation in 4‐position of 2,5‐dimethyl‐1,2,3‐diazaphosphole 70. The lithiated 1,2,4‐diazaphospholes and 3,4‐dihydro‐1,2,3‐diazaphospholes were coupled with MeI, ClSiMe 3 and chlorostannyl‐3‐diethylboryl‐2‐pentene,70 the 4‐lithio‐3,4‐dihydro‐1,2,3‐diazaphospholes also with CO 2 or protonated (with HCOOH)66 to give the corresponding substitution products. The boryl group did not coordinate at the σ 2 P atom of the 1,2,4‐diazaphosphole derivative, underlining the low basicity of σ 2 P, whereas the homologous triazole and the dihydro‐1,2,3‐diazaphosphole derivative displayed N→B and σ 3 P→B coordination, respectively 70.…”

Notizen: Versuche zur Herstellung eines Alkenyl(dimethyl)zinnhydrids: Gibt es eine intramolekulare Sn–H–B-Brücke?/ Attempts at the Synthesis of an Alkenyl(dimethyl)tin Hydride: Is there an Intramolecular Sn–H–B Bridge?

“…Auch koordinative P -B- [5] und O -B-Wechselwirkungen [6 ] sind bereits belegt. W ir sind jetzt der Frage nach einer intram olekularen Hydrid-Brücke für X = H (2) nachgegangen.…”