DTBB-catalysed lithiation of chlorinated benzylic chlorides, alcohols, thiols or amines

The reaction of chlorinated benzyl chlorides (1) with an excess of lithium powder and a catalytic amount of DTBB (4 mol %) in the presence of different electrophiles [(PrCHO)-C-i, (BuCHO)-C-t, Et2CO, (CH2)(5)CO, PhCOMe, Me3SiCl] in THF at -50 degrees C followed by hydrolysis with water leads to the corresponding compounds 2. When the same DTBB-catalysed lithiation is applied to several chlorinated benzylic alcohols or mercaptans (4 or 5) it is necessary to deprotonate the starting material with (BuLi)-Li-n; treatment of the resulting anions or amine 6 as above, but at -78 degrees C, leads to the expected reaction products 8, after reaction with different electrophiles [(PrCHO)-C-i, (BuCHO)-C-t, Et2CO, (CH2)(5)CO, PhCOMe, Me2SiCl] and fnal hydrolysis with water. (C) 1998 Elsevier Science Ltd. All rights reserved.