IMIDOYLLITHIUMS - MASKED ACYLLITHIUM REAGENTS

The reaction of chloroimines 1 with an excess of lithium powder and a catalytic amount of naphthalene (4 mol %) in THF at -78 degrees C lead s to the corresponding imidoyllithium intermediates 2, which by treatm ent with different electrophiles [(PrCHO)-C-i, (BuCHO)-C-t, n-C5H11CHO ,, PhCHO, Et2CO, (CH2)(5)CO, EtOCOCl, MeOCSCl, n-C7H15CON(Me)OMe] at - 78 to 20 degrees C and final hydrolysis with water affords functionaly sed imines 3. For starting material la is necessary to filter off the excess of lithium at the end of the lithiation step in order to get co mpounds 3, without filtration amines 4 are the reaction products isola ted. Hydrolysis of compounds 3 either during chromatographic purificat ion or by acidic hydrolysis (2 N HCl, THF) gives the expected function alised ketones 5. (C) 1997 Elsevier Science Ltd.