An allylic C–H acyloxylation of terminal alkenes with 4-nitrobenzoic acid was assisted by a bidentate-sulfoxide-ligated palladium catalyst combined with 1,4-benzoquinone and Ag₂CO₃ under mild reaction conditions. The catalytic activity was remarkably enhanced by Ag₂CO₃ as an additive and 4-nitrobenzoic acid as a carboxylate source; both components were essential to exhibiting high catalytic activity, high branch selectivity, and a wide substrate scope with low loading of the palladium catalyst. Branch-selective allylic acyloxylation of ethyl 7-octenoate (1a) gave the product which was led to ethyl 6,8-dihydroxyoctanoate (5), a useful synthetic intermediate of (R)-α-lipoic acid.

中文翻译：

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碳酸银和对硝基苯甲酸加速钯催化烯丙基C-H酰氧基化的作用

在温和的反应条件下，末端烯烃与 4-硝基苯甲酸的烯丙基 C-H 酰氧基化反应由双齿亚砜连接的钯催化剂与 1,4-苯醌和 Ag ₂ CO ₃组合辅助。Ag ₂ CO ₃作为添加剂和4-硝基苯甲酸作为羧酸盐源显着提高了催化活性；这两种组分对于表现出高催化活性、高支链选择性和钯催化剂负载量低的宽底物范围都是必不可少的。7-辛烯酸乙酯 ( 1a ) 的支链选择性烯丙基酰氧基化得到产物 6,8-二羟基辛酸乙酯 ( 5 )，这是一种有用的合成中间体 ( R)-α-硫辛酸。