Naphthalene-catalysed lithiation of carbamoyl and thiocarbamoyl chlorides under Barbier-type reaction conditions

The reaction of different carbamoyl or thiocarbamoyl chlorides 1 with carbonyl compounds or imines 2 in the presence of an excess of lithium powder and a catalytic amount of naphthalene (3 mol %) in THF at -78 degrees C leads, after hydrolysis with water, to the expected alpha-hydroxy or alpha-amino amides 3, respectively. In the case of allylic or benzylic derivatives 1a,c, when longer reaction times are used, the corresponding products 4 resulting from a deallylation or debenzylation are obtained. The use of DMF or phenyl isocyanate as electrophiles affords substituted oxamides 5. Finally, when previously to the hydrolysis an excess of an alkyl chloride is added to the reaction mixture, 1,2-diols 6 are formed resulting from a final double addition of the in situ generated alkyllithium to the alpha-hydroxy amide initially formed. Copyright (C) 1996 Elsevier Science Ltd