SYNTHESIS OF NOVEL HETEROCYCLES BY THE REACTION OF N,C-DILITHIO-2-ALLYLPYRROLE WITH ELECTROPHILES

N,C,-dilithio-2-allylpyrrole (1) in THF reacts selectively with variou s element halides to give Z-isomers, and in the case of element dihali des (Me2SiCl2, Me2SnCl2, Cp2ZrCl2) or SiCl4 to give new heterobicycles [E = Si (7), Sn (8), Zr (12)] or the spirosilane 6. Treatment of 1 wi th triethoxyborane gives the heterobicyclic borate 9 which reacts with Me3SiCl to give the heterobicyclic ethoxyborane 10. The synthetic pot iential of 8 is shown by its transformation to the heterobicyclic ethy lborane 11. All compounds were characterized by multinuclear magnetic resonance, including the application of modified (Hahn-echo extended) polarization transfer pulse sequences for measurement of (1)J(Si-29,N- 15), (1)J(Sn-119,N-15) and 2D C-13/H-1 heteronuclear shift correlation s for the determination of signs of coupling constants (n)J(Sn-119,C-1 3) and (n+1)J(Sn-119, H-1).