Enantioselective syntheses of substituted γ-butyrolactones
Enantioselective syntheses of substituted γ-butyrolactones
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DOI：
10.1002/jccs.200000006
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发表时间：
2000-02-01
影响因子：
1.8
通讯作者：
Ohwa, M
中科院分区：
文献类型：
--
作者：
Eliel, EL;Bai, X;Ohwa, M
前述手性2-酰基氧硫杂环己烷5（方案I）用于γ-丁内酯的两种不同的对映选择性合成。在一种合成中，格氏加成、裂解和还原为甲醇RR 'C（OH）CH 2 OH，然后进行甲苯磺酰化、丙二酸酯同系化、内酯化和除去甲氧羰基，得到光学活性的γ-内酯。在第二种合成中，烯醇化溴镁与酮5反应生成β-羟基酯，通过适当的还原和裂解顺序（方案II）将其转化为光学活性α-或β-羟基-γ-内酯。
The previously described chiral 2-acyloxathianes 5 (Scheme I) are used in two different enantioselective syntheses of gamma-butyrolactones. In one synthesis, Grignard addition, cleavage and reduction to carbinols RR'C(OH)CH2OH is followed by tosylation, malonate homologation, lactonization, and removal of the carbomethoxy group to give optically active gamma-lactones. A modification of this synthesis (Scheme I) leads to optically active alpha-methyl ene-gamma-lactones.In the second synthesis, reaction of a bromomagnesium enolate with ketones 5 leads to beta-hydroxyesters, which, by appropriate sequences of reduction and cleavage (Scheme II) are converted to optically active alpha- or beta-hydroxy-gamma-lactones.