Main group heterocycles from lithiated phosphinimines

Reaction of the phosphinimines (Me)tBu(2)PNSiMe(3) (1), (Me)tBu(2)PNC(6)H(2)Me(3) (3), and (PhCH2)tBu(2)PNSiMe(3) (6) with nBuLi and subsequently (C6F5)(2)BCl affords the four-membered heterocycles [((C6F5)(2)BCH2)tBu(2)PNSiMe(3)] (2), [((C6F5)(2)BCH2)tBu(2)PNC(6)H(2)Me(3)] (5), and [((C6F5)(2)BCH(Ph))t-Bu2PNSiMe3] (7), respectively. The related phosphinimine (iPr)tBu(2)PNSiMe(3) (8) reacts with tBuLi to give (LiCMe2)tBu(2)PNSiMe(3) (9), which reacts with (C6F5)(2)BCl to yield the five-membered heterocycle [((C6F5)(2)BCH2CH(Me))tBu(2)PNSiMe(3)] (10). Similarly, the species [(Me2AlCMe2)iPr(2)PNSiMe(3)] (12) and [((Me2N)(2)BCMe2)iPr(2)PNSiMe(3)] (13) were prepared from lithiation of the phosphinimine iPr(3)PNSiMe(3) (11). In exploring the chemistry of these heterocycles, compound 2 reacts with [Me3NH]Cl and MeOH to open the heterocycle, giving [(C6F5)(2)B(Cl)CH2PtBu2NH(SiMe3)] (14) and ((C6F5)(2)B(OMe)CH2)tBu(2)PNH(2) (15), respectively. Subsequent treatment of 15 with Me3SiCl affords the species ((C6F5)(2)B(Cl)CH2)tBu(2)PNH(2) (16), while treatment of 16 with nBuLi gives [((C6F5)(2)BCH2)tBu(2)PNH)] (17). Compound 17 coordinates AlMe3 to give ((C6F5)(2)BCH2)tBu(2)PNH](AlMe3) (18), while 15 reacts with AlMe3 to give the six-membered heterocycle [((C6F5)(2)B(OMe)CH2)tBu(2)PNH)(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.