a All compounds were identified by IR, NMR, and accurate mass spectral measurements. Known compounds (aldehydes) were derivatized (2, 4-DNP). Yields refer to isolated material at least 90% pure (NMR, TLC). A representative experiment follows. Clilorometliyltrimethylsilane (0.75 g, 6.14 mmol) in dry THF (8 mL) at-78" C under N, was treated with sec-butyllithium in cyclohexane (4.50 mL, 6.75" 01, 1.5 M solution) followed ...
