The Lewis acid promoted cyclodimerization of monoalkyl-substituted alkynes and cocyclodimerization of monoalkyl (ary1)-and dialkyl-substituted alkynes are described. It has been found that the corresponding aluminum halide u complexes of the cyclobutadienea react with activated nitriles, eg, ethyl cyanoformate, to yield substituted pyridines. The substitution pattern of the pyridines formed constitutes the basis of the proposed ...
