4-alkyloxycarbonyl-2-oxetanones with two stereogenic centers as precursors of malic acid alkyl esters polystereoisomers.
作者:Sandrine Cammas、Karine Boutault、François Huet、Philippe Guérin
DOI:10.1016/0957-4166(94)80129-0
日期:1994.8
(2-methylbutyl) in the course of a β-substituted-β-lactone synthesis route. Different stereoisomers of the 4-[(2′-methyl)butyloxycarbonyl-2-oxetanone have been prepared and characterized. It has been shown by using 400 MHz 1H NMR and Eu(hfc)3 as chiral shift reagent that enantiomeric or diastereomeric excess as high as 98 % could be retained during the synthesis route according to the specific experimental conditions
从外消旋,(R)或(S)天冬氨酸或苹果酸作为手性合成子开始,并通过引入不对称烷基酯基团(2-甲基丁基),制备了含有两个立体异构中心的外消旋和旋光的4-烷氧基羰基-2-氧杂庚烷。在β-取代的-β-内酯合成路线中。已经制备并表征了4-[((2'-甲基)丁氧基羰基-2-氧杂环丁烷酮]的不同立体异构体。通过使用400 MHz 1 H NMR和Eu(hfc)3进行了显示作为手性转移试剂,根据特定的实验条件,在合成过程中可以保留高达98%的对映体或非对映体过量。通过单体进料的阴离子开环聚合反应制备了高分子量外消旋和旋光性聚(2-甲基丁基β-苹果酸酯)。最后,已经表明,可以通过将4-[((2'-甲基)丁氧基羰基] -2-氧杂环丁酮与4-[(2'-甲基)丁氧基羰基] -2-氧杂环丁烷共聚而获得外消旋或旋光的聚(2-甲基丁基β-苹果酸酯-β-苹果酸)。 4-苄氧基羰基-2-氧杂环丁酮和苄基保护基的进一步催化氢解。