Powerful Ti-crossed Claisen condensation between ketene silyl acetals or thioacetals and acid chlorides or acids
Powerful Ti-crossed Claisen condensation between ketene silyl acetals or thioacetals and acid chlorides or acids
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DOI：
10.1021/ol0619361
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发表时间：
2006-11-09
期刊：
影响因子：
5.2
通讯作者：
Tanabe, Yoo
中科院分区：
文献类型：
--
作者：
Iida, Akira;Nakazawa, Syogo;Tanabe, Yoo
在烯酮甲硅烷基缩醛（KSA）和酰氯之间成功地进行了强有力的Ti-交叉克莱森缩合，以良好的产率（46个实施例; 41-98%产率）得到α-单烷基化酯和在化学上不利的（较难获得的）α，α-二烷基化β-酮酯。烯酮甲硅烷基硫代缩醛（KSTA）和酰氯之间的密切相关的反应也顺利进行，得到α-单烷基化和α，α-二烷基化β-酮基硫代酯（21个实施例; 61-97%产率）。将本方案扩展到KSA与羧酸的直接缩合（14个实施例; 71-97%产率）。
A powerful Ti-crossed Claisen condensation between ketene silyl acetals (KSAs) and acid chlorides was successfully performed to give alpha-monoalkylated esters and thermodynamically unfavorable (less accessible) alpha,alpha-dialkylated, beta-keto esters in good yield (46 examples; 41-98% yield). A closely related reaction between ketene silyl thioacetals (KSTAs) and acid chlorides also proceeded smoothly to give alpha-monoalkylated and alpha,alpha-dialkylated beta-keto thioesters (21 examples; 61-97% yield). The present protocol was extended to the direct condensation of KSAs with carboxylic acids (14 examples; 71-97% yield).