Macrocycles, 1. Macrocyclic polymerizations of (thio)lactones – stepwise ring expansion and ring contraction
Macrocycles, 1. Macrocyclic polymerizations of (thio)lactones – stepwise ring expansion and ring contraction
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大环，1. (硫代)内酯的大环聚合——逐步扩环和缩环
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
Nicole Schittenhelm
中科院分区：
文献类型：
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作者：
H. Kricheldorf;Soo;Nicole Schittenhelm
以氧化二丁锡和1,2-乙二醇、1,3-丙二醇或1,4-丁二醇为原料制备了2,2-二丁基-2-锡-1,3-二氧杂环烷。这些锡杂环通过逐步插入与双摩尔量的γ-硫代丁内酯发生化学计量反应。与γ-硫代丁内酯相反，过量的e-硫代己内酯导致了额外的插入步骤，即硫代内酯的聚合。用季戊四醇衍生的螺环烷进行了类似的插入反应。在没有化学计量中间体的情况下，e-己内酯发生了大环聚合。当2,2-二丁基锡-二氧杂烷与等摩尔量的1,3-二硫腙反应时，插入步骤紧接着发生缩环反应，生成2-锡-1,3-二硫烷和碳酸三亚甲基，并立即聚合。将该反应序列应用于大环锡纳聚e-己内酯，得到了与2,2-二丁基-2-锡纳-1,3-二thiane相结合的无锡大环。这个反应顺序允许合成无毒，可生物降解的大环聚酯。
2,2-Dibutyl-2-stanna-1,3-dioxacycloalkanes were prepared from dibutyltin oxide and 1,2-ethanediol, 1,3-propanediol or 1,4-butanediol. These tin heterocycles reacted stoichiometrically with double molar amounts of γ-thiobutyrolactone by a stepwise insertion. In contrast to γ-thiobutyrolactone an excess of e-thiocaprolactone resulted in additional insertion steps, i.e., polymerization of the thiolactone. Analogous insertion reactions were performed with a spirocyclic stannoxane derived from pentaerythritol. With e-caprolactone macrocyclic polymerization took place without stoichiometric intermediates. When the 2,2-dibutyl-stanna-dioxepane was reacted with an equimolar amount of 1,3-dithian-2-one, the insertion step was immediately followed by a ring contraction reaction yielding 2-stanna-1,3-dithiane and trimethylene carbonate which polymerized immediately. The application of this reaction sequence to macrocyclic stanna poly(e-caprolactone) yielded tin-free macrocycles along with 2,2-dibutyl-2-stanna-1,3-dithiane. This reaction sequence allows the synthesis of nontoxic, biodegradable macrocyclic polyesters.