Synthesis of novel heterocycles by the reaction of N,C-dilithio-2-allylpyrrole with electrophiles
作者:Bernd Wrackmeyer、Iris Ordung、Bernd Schwarze
DOI:10.1016/s0022-328x(96)06733-2
日期:1997.4
N,C,-dilithio-2-allylpyrrole (1) in THF reacts selectively with various element halides to give Z-isomers, and in the case of element dihalides (Me2SiCl2, Me2SnCl2, Cp2ZrCl2) or SiCl4 to give new heterobicycles [E = Si (7), Sn (8), Zr (12)] or the spirosilane 6. Treatment of 1 with triethoxyborane gives the heterobicyclic borate 9 which reacts with Me3SiCl to give the heterobicyclic ethoxyborane 10. The synthetic potiential of 8 is shown by its transformation to the heterobicyclic ethylborane 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 correlations for the determination of signs of coupling constants (n)J(Sn-119,C-13) and (n+1)J(Sn-119, H-1).