Synthesis of stereoregular poly[(2S,3S)‐benzyl β‐3‐methylmalate]

Abstract
The asymmetric lactone (3 S, 4 R)‐3‐methyl‐4‐benzyloxycarbonyl‐2‐oxetanone (6) was anionically polymerized to give an insoluble, crystalline, highly isotactic polymer with (2 S, 3 S)‐benzyl β‐3‐methylmalate repeating units. Solubility was achieved by copolymerization of 6 with the recemic (R, S)‐butyl malolactonate (7). The semicrystalline copolymer was characterized (M̄n = 107 000, Tg = 29,6°C, Tm = 161°C, [α] = 1,5 deg · dm−1 · g−1 · cm3) and its stereosequence investigated by 13C NMR.