The Stable (Phosphino)(Silyl)Carbene As A Useful Building Block: Synthesis And Reactivity of 2-Phosphorus-Substituted 2H-Azirines
作者:Valérie Piquet、Antoine Baceiredo、Heinz Gornitzka、Françoise Dahan、Guy Bertrand
DOI:10.1002/chem.19970031106
日期:1997.11
Abstract[Bis(dicyclohexylamino)phosphino]trimethylsilylcarbene (1) reacts with benzonitrile leading to the corresponding 2‐phosphino‐2H‐azirine 3 in 85% yield. Treatment of 3 with trifluoro‐methanesulfonic acid, methyl trifluoro‐methanesulfonate, or elemental sulfur leads to the P‐hydrogeno‐2‐phosphonio‐,P‐methyl‐2‐phosphonio‐, or 2‐thioxo‐phosphoranyl‐2H‐azirine (4, 5, and 7) in 77, 87, and 91% yields, respectively. Irradiation of 3 gives rise to the 1,2λ5‐azaphosphete 8 (98% yield). Treatment of 3 with BF3·OEt2, BH3·SMe2, Lawesson's reagent, or methyl isothiocyanate gives heterocycles 9 (90% yield), 10 (76% yield), 12 (83% yield), or 13 (80% yield), while under the same experimental conditions, heterocycle 8 reacts with the same reagents to give 9 (82% yield), 11 (83% yield), 12 (86% yield), and 15 (56% yield), respectively. Thermolysis of the P‐hydrogeno‐2‐phosphonio‐2H‐azirine 4 at 55°C leads to the cationic, four‐membered heterocycle 17 (96% yield), while photolysis of the P‐methylazirine analogue 5 in the presence of dimethyl acetylenedicarboxylate affords pyrrole 19 (64% yield). Irradiation of the thiox‐ophosphoranyl azirine 7 gives the 1,3,5λ5‐thiazaphosphole 20 in 79% yield. The influence of the coordination state of phosphorus on the reactivity of 2‐phosphorus‐substituted 2H‐azirines is studied.