Main Group Heterocycles from Lithiated Phosphinimines

Reaction of the phosphinimines (Me)tBu2PNSiMe3 (1), (Me)tBu2PNC6H2Me3 (3), and (PhCH2)tBu2PNSiMe3 (6) with nBuLi and subsequently (C6F5)2BCl affords the four-membered heterocycles [((C6F5)2BCH2)tBu2PNSiMe3] (2), [((C6F5)2BCH2)tBu2PNC6H2Me3] (5), and [((C6F5)2BCH(Ph))t-Bu2PNSiMe3]
(7), respectively. The related phosphinimine (iPr)tBu2PNSiMe3 (8) reacts with tBuLi to give (LiCMe2)tBu2PNSiMe3 (9), which reacts with (C6F5)2BCl to yield the five-membered heterocycle [((C6F5)2BCH2CH(Me))tBu2PNSiMe3] (10). Similarly, the species [(Me2AlCMe2)iPr2PNSiMe3] (12) and [((Me2N)2BCMe2)iPr2PNSiMe3] (13) were prepared from lithiation of the phosphinimine iPr3PNSiMe3 (11). In
exploring the chemistry of these heterocycles, compound 2 reacts with [Me3NH]Cl and MeOH to open
the heterocycle, giving [(C6F5)2B(Cl)CH2PtBu2NH(SiMe3)] (14) and ((C6F5)2B(OMe)CH2)tBu2PNH2 (15),
respectively. Subsequent treatment of 15 with Me3SiCl affords the species ((C6F5)2B(Cl)CH2)tBu2PNH2
(16), while treatment of 16 with nBuLi gives [((C6F5)2BCH2)tBu2PNH)] (17). Compound 17 coordinates
AlMe3 to give ((C6F5)2BCH2)tBu2PNH](AlMe3) (18), while 15 reacts with AlMe3 to give the six-membered
heterocycle [((C6F5)2B(OMe)CH2)tBu2PNH)(AlMe2)] (19). This chemistry is discussed and the implications
are considered. X-ray crystallographic data are reported for 2, 5, 7, 9, 10, 14, and 17.