RING-CLOSURE REACTIONS. XX. AN EFFICIENT SYNTHESIS OF MANY-MEMBERED AZACYCLOALKANES
An efficient cyclization of N-tosyl-ω-bromoalkylamines to N-tosylazacycloalkanes in the presence of a combination of EtOK/K2CO3 in Me2SO solution is described.This base-solvent system permitted the high-dilution conditions favourable to cyclization to be attained with a conveniently high rate of feed of the bifunctional reactants into the reaction medium.Yields are very good for the large rings, and still satisfactory, although significantly lower, for the medium-sized rings.