Morgan S. Young, Anne M. LaPointe, Samantha N. MacMillan and Geoffrey W. Coates*,
{"title":"双金属镁催化剂对 β-丁内酯的高对映选择性聚合:有利对映体和不利对映体之间的相互依赖关系。","authors":"Morgan S. Young, Anne M. LaPointe, Samantha N. MacMillan and Geoffrey W. Coates*, ","doi":"10.1021/jacs.4c04716","DOIUrl":null,"url":null,"abstract":"<p >Herein, we report that (<i>S</i>,<i>S</i>)-prophenolMg<sub>2</sub>(μ-O<sup><i>n</i></sup>Bu)(THF)<sub>2</sub> ((<i>S</i>,<i>S</i>)-<b>1</b>, prophenol = (<i>S</i>,<i>S</i>)-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-methylphenol) is a highly enantioselective (<i>k</i><sub>R</sub>/<i>k</i><sub>S</sub> = 140) precatalyst for ring-opening polymerization of <i>rac</i>-β-butyrolactone (β-BL) to isotactic poly(3-hydroxybutyrate) (<i>i</i>-PHB), a high performance, biodegradable polyester. Precatalyst (<i>S</i>,<i>S</i>)-<b>1</b> polymerizes (<i>R</i>)-β-BL with an inversion of stereochemistry to (<i>S</i>)<i>-</i>PHB with a <i>m</i>% (percentage of adjacent linkages with a <i>meso</i> configuration) of 98% at 41% conversion and <i>T</i><sub>m</sub> of 165 °C under a variety of conditions. Complex (<i>S</i>,<i>S</i>)-<b>1</b> demonstrates unique polymerization kinetics, as it does not polymerize the preferred enantiomer, (<i>R</i>)-β-BL, alone. Mechanistic studies revealed that (<i>S</i>)-β-BL is needed to convert (<i>S</i>,<i>S</i>)-<b>1</b> into the active enantioselective polymerization catalyst. To the best of our knowledge, (<i>S</i>,<i>S</i>)-<b>1</b> produces <i>i</i>-PHB with the highest degree of isotacticity observed from a polymerization of <i>rac</i>-β-BL. This study informs the design and understanding of future enantioselective and earth-abundant metal catalysts for ring-opening polymerization of β-lactones.</p>","PeriodicalId":49,"journal":{"name":"Journal of the American Chemical Society","volume":null,"pages":null},"PeriodicalIF":14.4000,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Highly Enantioselective Polymerization of β-Butyrolactone by a Bimetallic Magnesium Catalyst: An Interdependent Relationship Between Favored and Unfavored Enantiomers\",\"authors\":\"Morgan S. Young, Anne M. LaPointe, Samantha N. MacMillan and Geoffrey W. Coates*, \",\"doi\":\"10.1021/jacs.4c04716\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Herein, we report that (<i>S</i>,<i>S</i>)-prophenolMg<sub>2</sub>(μ-O<sup><i>n</i></sup>Bu)(THF)<sub>2</sub> ((<i>S</i>,<i>S</i>)-<b>1</b>, prophenol = (<i>S</i>,<i>S</i>)-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-methylphenol) is a highly enantioselective (<i>k</i><sub>R</sub>/<i>k</i><sub>S</sub> = 140) precatalyst for ring-opening polymerization of <i>rac</i>-β-butyrolactone (β-BL) to isotactic poly(3-hydroxybutyrate) (<i>i</i>-PHB), a high performance, biodegradable polyester. Precatalyst (<i>S</i>,<i>S</i>)-<b>1</b> polymerizes (<i>R</i>)-β-BL with an inversion of stereochemistry to (<i>S</i>)<i>-</i>PHB with a <i>m</i>% (percentage of adjacent linkages with a <i>meso</i> configuration) of 98% at 41% conversion and <i>T</i><sub>m</sub> of 165 °C under a variety of conditions. Complex (<i>S</i>,<i>S</i>)-<b>1</b> demonstrates unique polymerization kinetics, as it does not polymerize the preferred enantiomer, (<i>R</i>)-β-BL, alone. Mechanistic studies revealed that (<i>S</i>)-β-BL is needed to convert (<i>S</i>,<i>S</i>)-<b>1</b> into the active enantioselective polymerization catalyst. To the best of our knowledge, (<i>S</i>,<i>S</i>)-<b>1</b> produces <i>i</i>-PHB with the highest degree of isotacticity observed from a polymerization of <i>rac</i>-β-BL. This study informs the design and understanding of future enantioselective and earth-abundant metal catalysts for ring-opening polymerization of β-lactones.</p>\",\"PeriodicalId\":49,\"journal\":{\"name\":\"Journal of the American Chemical Society\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":14.4000,\"publicationDate\":\"2024-06-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the American Chemical Society\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/jacs.4c04716\",\"RegionNum\":1,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the American Chemical Society","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/jacs.4c04716","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
Highly Enantioselective Polymerization of β-Butyrolactone by a Bimetallic Magnesium Catalyst: An Interdependent Relationship Between Favored and Unfavored Enantiomers
Herein, we report that (S,S)-prophenolMg2(μ-OnBu)(THF)2 ((S,S)-1, prophenol = (S,S)-2,6-bis[2-(hydroxydiphenylmethyl)pyrrolidin-1-ylmethyl]-4-methylphenol) is a highly enantioselective (kR/kS = 140) precatalyst for ring-opening polymerization of rac-β-butyrolactone (β-BL) to isotactic poly(3-hydroxybutyrate) (i-PHB), a high performance, biodegradable polyester. Precatalyst (S,S)-1 polymerizes (R)-β-BL with an inversion of stereochemistry to (S)-PHB with a m% (percentage of adjacent linkages with a meso configuration) of 98% at 41% conversion and Tm of 165 °C under a variety of conditions. Complex (S,S)-1 demonstrates unique polymerization kinetics, as it does not polymerize the preferred enantiomer, (R)-β-BL, alone. Mechanistic studies revealed that (S)-β-BL is needed to convert (S,S)-1 into the active enantioselective polymerization catalyst. To the best of our knowledge, (S,S)-1 produces i-PHB with the highest degree of isotacticity observed from a polymerization of rac-β-BL. This study informs the design and understanding of future enantioselective and earth-abundant metal catalysts for ring-opening polymerization of β-lactones.
期刊介绍:
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