A facile and efficient protocol to synthesize C2‐phosphorylated 2,3‐2H‐chromones is discovered via Brønsted acid‐promoted tandem addition/cyclization of enaminones with H‐phosphine oxides. The reaction exhibits a broad scope, good functional group tolerance, and good yields, and features ability of a gram‐scaled synthesis. Results of mechanistic study reveal that the reaction initially undergoes intramolecular cyclization to form chromone 5, which can subsequently be reacted with 2a to yield C2‐phosphorylated 2,3‐2H‐chromones through intermolecular addition.

中文翻译：

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Brønsted 酸促进烯胺与 H-膦氧化物的串联环化/烯胺加成反应以合成 C2 磷酸化的 2,3-2H-色酮


通过 Brønsted 酸促进烯胺与 H-膦氧化物的串联加成/环化，发现了一种合成 C2 磷酸化 2,3-2H-色酮的简单有效的方案。该反应范围广、官能团耐受性好、产率好，具有克级合成能力。机理研究结果表明，该反应最初经历分子内环化形成色酮 5，随后可与 2a 反应，通过分子间加成产生 C2 磷酸化的 2,3-2H-色酮。