Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA.
Chemistry. 2022 Aug 1;28(43):e202200941. doi: 10.1002/chem.202200941. Epub 2022 Jun 14.
Asymmetric 1,2-carbamoyl rearrangement of lithiated 2-alkenyl carbamates has been investigated. Deprotonation of chiral 2-alkenyl oxazolidine carbamates with sec-butyllithium in ether at -78 °C followed by warming of the resulting 1-lithio-2-alkenyl derivatives to room temperature resulted in 1,2-carbamoyl rearrangement to provide α-hydroxy amides. The rearrangement proceeded with excellent diastereoselectivity and in good to excellent isolated yield of the α-hydroxy amide derivatives. The substrate scope of the reaction was investigated with a variety of 2-alkenyl and benzyl oxazolidine carbamates. A stereochemical model is provided to explain the stereochemical outcome associated with the rearrangement. Acid-catalyzed removal of the chiral oxazolidine afforded α-hydroxy acid in high optical purity.
我们研究了锂化 2-烯基氨基甲酸酯的不对称 1,2-氨基甲酰重排。在-78°C 下，用仲丁基锂将手性 2-烯基恶唑烷氨基甲酸酯在醚中脱质子，然后将得到的 1-锂-2-烯基衍生物升温至室温，导致 1,2-氨基甲酰重排，生成α-羟基酰胺。该重排具有极好的非对映选择性，并且α-羟基酰胺衍生物的分离产率也很好。研究了各种 2-烯基和苄基恶唑烷氨基甲酸酯作为反应底物的范围。提供了一个立体化学模型来解释与重排相关的立体化学结果。酸催化去除手性恶唑烷可得到光学纯度高的α-羟基酸。
