A novel approach is reported for the synthesis of the highly isotactic poly(racemic lactic acid) [P(rac-LAA)] from racemic 2,2,5-trimethyl-1,3-dioxolan-4-one by using achiral homosalen–Al catalysts. The polymerization proceeded through two steps: stereoselective ring-opening and deacetonation. The effects of substituents on the homosalen–Al catalyst were clarified regarding the polymerization rates and polydispersity of the obtained P(rac-LAA), but were still unclear regarding the iso-stereoselectivity. The P(rac-LAA) obtained by using an isopropyl-substituted homosalen–Al catalyst showed the highest isotacticity (P _m = 0.96), a moderate number-average molecular weight (M _n = 6,200), and broad polydispersity (PDI = 2.2₀). Differential scanning calorimetric measurements indicated that the polymer was semicrystalline with a melting temperature of 156 °C.

报道了一种利用非手性的homosalen从外消旋2,2,5-三甲基-1,3-二氧戊环-4-酮合成高度全同立构聚（外消旋乳酸）[P( rac -LAA)]的新方法。铝催化剂。聚合反应通过两个步骤进行：立体选择性开环和脱丙酮。取代基对Homosalen-Al催化剂的影响在所得P( rac -LAA)的聚合速率和多分散性方面得到阐明，但在异构立体选择性方面仍不清楚。使用异丙基取代的homosalen-Al催化剂得到的P( rac -LAA)表现出最高的全同立构规整度( P _m = 0.96)、适中的数均分子量( M _n = 6,200) 和广泛的多分散性 (PDI = 2.2 ₀ )。差示扫描量热测量表明该聚合物是半结晶的，熔化温度为156℃。