R = alkyl, aryl) are obtained via the nucleophilic fragmentation of tetracationic tetraphosphetane [(LC–P)4][OTf]4 (2[OTf]4) with tertiary phosphanes. They act as [LC–P]+ transfer reagents in phospha-Wittig-type reactions, when converted with various thiocarbonyls, giving unprecedented cationic phosphaalkenes [LC–P═CR2]+ (5a-f[OTf]) or phosphanides [LC–P–CR(NR2′)]+ (6a-d[OTf]). Theoretical calculations
得到阳离子
咪唑鎓基(膦酰基)-
磷酯[L C –P–PR 3 ] + ( 1a–e + , L C = 4,
5-二甲基-1,3-
二异丙基咪唑鎓-2-基; R = 烷基、芳基)通过四阳离子四膦烷 [( LC –P) 4 ][OTf] 4 ( 2 [OTf] 4 ) 与叔膦的亲核裂解。它们在
磷维蒂希型反应中充当 [ LC –P] +转移试剂,当与各种
硫代羰基转化时,产生前所未有的阳离子
磷烯烃 [LC –P =CR 2 ] + ( 5a-f [OTf]) 或
磷化物[ LC –P–CR(NR 2 ′ )] + ( 6a-d [OTf])。理论计算表明三元环
硫代膦是该反应的关键中间体。为了检验这一假设,用与
硫酮同瓣的
磷烯处理 [ LC –P–PPh 3 ] + ,可以分离二
磷烷盐11a,b [OTf]。此外,初步研究表明,当用[ Pd (PPh 3 ) 4 ]和[Pt(PPh 3 ) 3 ],其中中性
磷烯的类似配合物很少。