Synthetic, structural and theoretical studies on new aromatic 1,2,4-azadiphosphole ring systems: crystal and molecular structure of P2C2But2NPh

A Novel Approach to 1,2,4-Thiadiphospholes and Functionalized 1,2-Thiaphospholes

“…of thiadiphosphole 3a and 2 equiv. of cycloheptyne (21). The 31 P{ 1 H} NMR spectrum contained two signals split into doublets by a 2 J P,P coupling of 1.5 Hz, which indicated that both phosphorous atoms of the heterocycle 3a were incorporated in the molecular framework of 23.…”

“…) were required than for the 1,2,4-oxadiphospholes and the corresponding selenadiphospholes, on account of the aromatic character of 3 (NICS value comparable with that of furan [21] ).…”

“…(2)ϪP (3) 112.51 (12), S (7)ϪC (6)ϪP (3) 110.43(13), S(7)ϪC (6)ϪP (5) Treatment of the 1,2,4-thiadiphosphole 3a with 2 equiv. of cycloheptyne (21), generated in situ, afforded the cage compound 23 (Scheme 6), but no analogous reaction took place with higher cyclic acetylenes such as cyclooctyne. 31 P NMR monitoring already indicated that a reaction course different from that in the case of the thiadiphospholes 3 and the acetylenes 15 had taken place, because no signal was found for the tert-butylphosphaalkyne 1a.…”

“…31 P NMR monitoring already indicated that a reaction course different from that in the case of the thiadiphospholes 3 and the acetylenes 15 had taken place, because no signal was found for the tert-butylphosphaalkyne 1a. The required cycloheptyne (21) was generated oxidatively at Ϫ78°C from Scheme 6. Reaction between 3a and cycloheptyne (21) the amino-1H-triazole 20.…”

“…The required cycloheptyne (21) was generated oxidatively at Ϫ78°C from Scheme 6. Reaction between 3a and cycloheptyne (21) the amino-1H-triazole 20. The [4ϩ2] cycloaddition between 21 and 3a to afford the heteronorbornadiene system 22 is directly followed by a homo-DielsϪAlder reaction with an additional equivalent of cycloheptyne (21) to furnish the tetracyclic cage compound 23.…”