An efficient method for the synthesis of polysubstituted indolizines has been developed based on formal [4+2] annulation of 1-acetylaryl 2-formylpyrroles with enals, followed by oxidative aromatization. Pyridine-type six-membered rings were constructed in this transformation. This transition metal-free reaction features mild reaction conditions, a broad substrate scope, and excellent functional group tolerance. Notably, the formyl group is well tolerated under reaction conditions.

中文翻译：

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通过1-乙酰基芳基2-甲酰基吡咯和Enals的一锅反应轻松合成多取代的吲哚嗪。

基于1-乙酰芳基2-甲酰基吡咯与烯醛的正式[4 + 2]环合，然后进行氧化芳构化，已经开发了一种有效的合成多取代的吲哚嗪的方法。在该转化中构建了吡啶型六元环。这种无过渡金属的反应具有温和的反应条件，广泛的底物范围和出色的官能团耐受性。值得注意的是，甲酰基在反应条件下具有良好的耐受性。