Faculty of Pharmaceutical Sciences, Hokkaido University , Sapporo 060-0812, Japan.
J Am Chem Soc. 2017 May 3;139(17):6094-6097. doi: 10.1021/jacs.7b02775. Epub 2017 Apr 20.
Catalytic carboxylation of the allylic C(sp)-H bond of terminal alkenes with CO was developed with the aid of a Co/Xantphos complex. A wide range of allylarenes and 1,4-dienes were successfully transformed into the linear styrylacetic acid and hexa-3,5-dienoic acid derivatives in moderate to high yields, with excellent regioselectivity. The carboxylation showed remarkable functional group tolerability, so that selective addition to CO occurred in the presence of other carbonyl groups such as amide, ester, and ketone. Since styrylacetic acid derivatives can be readily converted into optically active γ-butyrolactones through Sharpless asymmetric dihydroxylation, this allylic C(sp)-H carboxylation showcases a facile synthesis of γ-butyrolactones from simple allylarenes via short steps.
在 Co/Xantphos 配合物的辅助下，发展了末端烯烃的烯丙位 C(sp)-H 键的催化羧化反应。通过该方法，一系列烯丙基芳烃和 1,4-二烯可以以中等到高产率、优异的区域选择性转化为线性苯乙烯基乙酸和己-3,5-二烯酸衍生物。该羧化反应对官能团具有很好的耐受性，因此在酰胺、酯和酮等其他羰基存在的情况下，CO 可以选择性地加成。由于苯乙烯基乙酸衍生物可以通过 Sharpless 不对称双羟化反应容易地转化为手性γ-丁内酯，因此该烯丙基 C(sp)-H 羧化反应展示了通过短步骤从简单的烯丙基芳烃简便合成γ-丁内酯的方法。
