'H and I3C NMR spectra were recorded on a Varian Gemini spectrometer (300 MHz); the chemical shifts (6) are reported in ppm relative to TMS; and coupling constants (J) are reported in Hz." P NMR spectra were recorded using 10% H, PO, in a sealed capillary as an internal standard; the chemical shifts are reported in ppm relative to H, PO,. Electrospray ionization mass spectrometry (ESI-MS) was carried out on a Perkin-Elmer (Norwalk, CT) ...
