To understand the ligand-controlled palladium-catalyzed coupling of o-bromobenzaldehyde, N-tosylhydrazone, and methanol to give methyl 2-benzylbenzoic ester or methyl ether, we herein investigated the mechanisms which account for how C–C and C–O bonds are formed and why bidentate dppf/dppb ligands afford ester, whereas P(o-tolyl)₃ ligand gives ether. The ester chemoselectivity of the bidentate ligands is attributed to the strong electron-donating effect that disfavors the C,Br-reductive elimination of the coupling intermediate of o-bromobenzaldehyde and N-tosylhydrazone.

中文翻译：

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了解钯催化邻溴代苯甲醛，N-甲苯磺酰hydr和甲醇的三组分反应中的化学选择性

为了理解邻位-溴苯甲醛，N-甲苯磺酰hydr和甲醇的配体控制的钯催化偶联，得到甲基2-苄基苯甲酸酯或甲基醚，我们在这里研究了解释CC和C-O键如何起作用的机理。二齿的dppf / dppb配体形成酯的原因，而P（邻甲苯基）₃配体生成醚的原因。二齿配体的酯化学选择性归因于强的给电子作用，该作用不利于邻溴苯甲醛和N-甲苯磺酰the的C，Br-还原消除。