Supplementary Material Available: X-ray data for 18-H and 18-F, 13C NMR spectra of (Z)-3- Ph, 10-F,(E)-and (Z)-ll-F, 13-H,(E)-and (2)-13-F, 17, and 18-H, and'H NMR spectra of (E)-and (2)-11-F and 14-H (at 600 MHz)(25 pages). Ordering information is given on any current masthead page.