β-内酯亲电体会与多种基于氮的亲核体发生区域选择性加成-消除(AE)或S N 2开环。伯胺和仲胺可促进AE开环,从而提供功能上与酰胺醇醛加合物相同的产品。叠氮化物和磺酰胺阴离子亲核试剂使S N 2内酯开环传递N保护的β-氨基酸衍生物。这些依赖亲核试剂的开环途径,再加上通过酰基卤-醛环缩合反应获得的富含大量庚酮的β-内酯的便捷途径,构成了不对称有机合成的通用方法。还描述了该反应技术在基于从AAC开环序列中出现的旋光性β-叠氮酸的β肽合成新方法中的应用。
Predicting the R/S absolute configuration in asymmetric bifunctional catalysis (ABC)
摘要:
A predictive model for assigning the R/S absolute configuration in chiral Lewis base-dependent asymmetric bifunctional catalysis (ABC) has been developed. Chiral Lewis base (LB*)-dependent ABC abolishes the chiral Lewis acid (LA*) component as the stereochemical determining factor in asymmetric catalysis. By correlating the constant LB* chirality to the facial preference for the LA*-bound carbonyl group for nucleophile delivery, the R/S absolute configuration of the products can be predicted a priori. (c) 2007 Elsevier Ltd. All rights reserved.
Predicting the R/S absolute configuration in asymmetric bifunctional catalysis (ABC)
作者:Yun-Ming Lin、Zhongtao Li、Julie Boucau
DOI:10.1016/j.tetlet.2007.05.131
日期:2007.7
A predictive model for assigning the R/S absolute configuration in chiral Lewis base-dependent asymmetric bifunctional catalysis (ABC) has been developed. Chiral Lewis base (LB*)-dependent ABC abolishes the chiral Lewis acid (LA*) component as the stereochemical determining factor in asymmetric catalysis. By correlating the constant LB* chirality to the facial preference for the LA*-bound carbonyl group for nucleophile delivery, the R/S absolute configuration of the products can be predicted a priori. (c) 2007 Elsevier Ltd. All rights reserved.
Divergent reaction pathways in amine additions to β-lactone electrophiles. An application to β-peptide synthesis
作者:Scott G. Nelson、Keith L. Spencer、Wing S. Cheung、Steven J. Mamie
DOI:10.1016/s0040-4020(02)00722-6
日期:2002.8
β-Lactone electrophiles are subject to regioselective addition–elimination (AE) or SN2 ring opening with various nitrogen-based nucleophiles. Primary and secondary amines promote AE ring opening to deliver products that are the functional equivalent of amide aldol adducts. Azide and sulfonamide anion nucleophiles engender SN2 lactone ring opening to deliver N-protected β-amino acid derivatives. These
β-内酯亲电体会与多种基于氮的亲核体发生区域选择性加成-消除(AE)或S N 2开环。伯胺和仲胺可促进AE开环,从而提供功能上与酰胺醇醛加合物相同的产品。叠氮化物和磺酰胺阴离子亲核试剂使S N 2内酯开环传递N保护的β-氨基酸衍生物。这些依赖亲核试剂的开环途径,再加上通过酰基卤-醛环缩合反应获得的富含大量庚酮的β-内酯的便捷途径,构成了不对称有机合成的通用方法。还描述了该反应技术在基于从AAC开环序列中出现的旋光性β-叠氮酸的β肽合成新方法中的应用。