Metallation reactions. Part X. Allylic metallation in the presence of amide groups: long range interactions

Abstract

The N-methylamide of linoleic acid is metallated by butyl-lithium in ether or in hexane α to the amide groups and/or at the doubly allylic position, without addition to the carbonyl group. The ratio of the products depends on the solvent. Metallations of NN-dimethyl-linoleamine were also obtained. The positions of carbonation of these lithium derivatives revealed a long-range effect of the functional groups. A series of octadecanoic acids with one additional carboxy-group in various positions in the chain was prepared for comparison. Products of metallation in the presence of tetramethylethylenediamine of the amide with the conjugated two double bonds gave addition of butyl-lithium to the diene.