The organocatalytic properties of unnatural α‐amino acids are reviewed. Post‐translational derivatives of natural α‐amino acids include 4‐hydroxy‐l‐proline and 4‐amino‐l‐proline scaffolds, and also proline homologues. The activity of synthetic unnatural α‐amino acid‐based organocatalysts, such as β‐alkyl alanines, alanine‐based phosphines, and tert‐leucine derivatives, are reviewed herein. The organocatalytic properties of unnatural monocyclic, bicyclic, and tricyclic proline derivatives are also reviewed. Several families of these organocatalysts permit the efficient and stereoselective synthesis of complex natural products. Most of the reviewed organocatalysts accelerate the reported reactions through covalent interactions that raise the HOMO (enamine intermediates) or lower the LUMO (iminium intermediates).

中文翻译：

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非天然α-氨基酸衍生的有机催化剂：范围和应用

综述了非天然α-氨基酸的有机催化性能。天然α-氨基酸的翻译后衍生物包括4-羟基-l-脯氨酸和4-氨基-l-脯氨酸支架，以及脯氨酸的同源物。合成的非天然α-基于氨基酸的有机催化剂，如β -烷基丙氨酸，基于丙氨酸-膦和活性叔亮氨酸衍生物，在本文中进行综述。还综述了非天然单环，双环和三环脯氨酸衍生物的有机催化性能。这些有机催化剂的几个家族允许复杂的天然产物的高效和立体选择性合成。大多数审查过的有机催化剂通过提高HOMO（烯胺中间体）或降低LUMO（亚胺中间体）的共价相互作用加速了已报道的反应。