In the first run, an aliquot examined by NMR after 15 min exhibited a pattern in the aromatic region attributed to cycloadduct 15 (ca. 38%) and lithiated isobenzofuran 12 (62%). After 37 min, tert-butyl alcohol was added, and this caused the ap-pearance of a singlet at 6 7.9, the furan proton of 11. This signal disappeared with a half-life of ca. 9 min, corresponding to a rate constant (11-15) of k,= 1.3 X sl (ca. 32" C). This experiment was repeated to confiim ...