ORTHO-BENZOQUINONE ADDUCTS, REARRANGEMENT AND ELIMINATION-REACTIONS OF 1,1,3-TRIMETHYL-1,3,2-DIAZAPHOSPHOLIDIN-1-IUM SALTS

The 1,1,3-trimethyl-1,3,2-diazaphospholidin-1-ium salts [Me2 activated NCH2CH2(Me)NPY]+ X- [1 (X = Br, Y = NEt2), 2 (X = [BPh4], Y = Me), 3 (X = [BPh4], Y = Ph), 4 (X = [BPh4], Y = NEt2), 5 (X = [BPh4], Y = tBu)] were treated with o-benzoquinones. The reaction of 1 with tetrachloro-o-benzoquinone furnished the spirophosphorane 6 with an intact N --> lambda(5)P donor-acceptor interaction. The reaction of 2, 3, and 4 with 3,5-di-tert-butyl-o-benzoquinone furnished [Me2 activated NCH2CH2(Me)NP(Y){O2C6H2(tBu)2}]+ [BPh4]- [8 (Y = Me), 9 (Y = Ph), 10 (Y = NEt2)]. The reaction of 5 with 3,5-di-tert-butyl-o-benzoquinone yielded 7 which exhibited no significant N --> lambda(5)P donor-acceptor interaction. The rearrangement product 11 was formed in small amounts during the reaction of 5 with tetrachloro-o-benzoquinone; 11 was also prepared by an alternative route. Thermolysis of the 1,1,3-trimethyl-1,3,2-diazaphospholidin-1-ium salts [Me2 activated NCH2CH2(Me)NPX]+ X- [14 (X = Br), 15 (X = I)] in vacuo led, with elimination of methyl halide, to the 1,3,2-diazaphospholidines 16 (X = Br) and 17 (X = I). The salts were characterized by FAB-MS.