Two complementary [3 + 2] annulation protocols between 3-oxoglutarates and cyclic γ-oxy-2-cycloalkenones, simply differing on the reaction temperature, are disclosed. These domino transformations allow C-C/O-C or C-C/C-C [3 + 2] annulations at will, via an intermolecular Pd-catalyzed C-allylation/intramolecular O- or C-1,4-addition sequence, respectively. In particular, exploiting the reversibility of the O-1,4-addition step, in combination with the irreversible C-1,4-addition/decarboxylation path, the intramolecular conjugate addition step could be diverted from the kinetic (O-alkylation) to the thermodynamic path (C-alkylation) thanks to a simple temperature increase. Crucial for the success of this bis-nucleophile/bis-electrophile [3 + 2] annulation is its well-defined step chronology in combination with the total chemoselectivity of the former step. This [3 + 2] C-C/O-C bond forming annulation protocol could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nucleophiles.

中文翻译：

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Pd 催化的 γ-oxy-2-环烯酮与 3-酮戊二酸的 [3 + 2] 环化的可切换选择性：CC/CC 与 CC/OC 键形成。


公开了3-氧代戊二酸和环状γ-氧基-2-环烯酮之间的两种互补的[3+2]成环方案，只是反应温度不同。这些多米诺骨牌转化允许分别通过分子间 Pd 催化的 C-烯丙基化/分子内 O-或 C-1,4-加成序列随意进行 CC/OC 或 CC/CC [3 + 2] 成环。特别是，利用O-1,4-加成步骤的可逆性，结合不可逆的C-1,4-加成/脱羧路径，分子内共轭加成步骤可以从动力学（O-烷基化）转向通过简单的温度升高实现热力学路径（C-烷基化）。这种双亲核试剂/双亲电子试剂 [3 + 2] 成环成功的关键是其明确的步骤时间顺序与前一步的总化学选择性相结合。这种 [3 + 2] CC/OC 键形成环化方案也可以扩展到 1,3,5-三酮以及 1,3-双-磺酰基丙-2-酮双亲核试剂。