Stereocontrolled synthesis of stereoregular, chiral analogs of nylon 5, 5 and nylon 5,6

Abstract

L-glutamic acid ( 1) was employed as a chiral template in the preparation of the pentachlorophenyl ester of (4 S)-carboxy-1,4-butirolactone ( 3), a key precursor of chiral analogs of nylon 5,5 and nylon 5,6. Stereocontrol in the synthesis of these polymers was achieved by chemoselective condensation of the ester group of 3 with aminoalcohols. The alcohol function of the resulting N-(hydroxyalkyl)amides ( 4 and 9) was converted into amine by tosylation, azide substitution and hydrogenolysis. The amino lactones 7 and 12 thus obtained were conveniently functionalized for the polycondensation, which led to the stereoregular, crystalline polyamides 8 and 13.