Chiral DMAP‐N‐oxides as Acyl Transfer Catalysts: Design, Synthesis, and Application in Asymmetric Steglich Rearrangement

• Published in: Angewandte Chemie International Edition Vol. 58; no. 9; pp. 2839 - 2843
• Main Authors: Xie, Ming‐Sheng, Zhang, Ye‐Fei, Shan, Meng, Wu, Xiao‐Xia, Qu, Gui‐Rong, Guo, Hai‐Ming
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 25.02.2019; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: acyl transfer; Amino acids; asymmetric catalysis; Asymmetry; Catalysis; Catalysts; Chemical synthesis; Chemistry; Chemistry, Multidisciplinary; Nitrogen; nucleophilic catalysis; organocatalysis; Oxides; Physical Sciences; Pyridines; rearrangement; Science & Technology; 4-(DIMETHYLAMINO)PYRIDINE; ENANTIOSELECTIVE SYNTHESIS; acyl transfer; ACYLATION; ANALOGS; asymmetric catalysis; NONENZYMATIC KINETIC RESOLUTION; AROMATIC-ALDEHYDES; organocatalysis; nucleophilic catalysis; SEC-ALCOHOLS; PYRIDINE CATALYSTS; DERIVATIVES; rearrangement
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201812864

A DMAP‐N‐oxide, featuring an α‐amino acid as the chiral source, was developed, synthesized and applied in asymmetric Steglich rearrangement. A series of O‐acylated azlactones afforded C‐acylated azlactones possessing a quaternary stereocenter in high yields (up to 97 % yield) and excellent enantioselectivities (up to 97 % ee). Compared to the widespread use of pyridine nitrogen, which serves as the nucleophilic site in the asymmetric acyl transfer reaction, we discovered that chiral DMAP‐N‐oxides, in which the oxygen now acts as the nucleophilic site, are efficient acyl transfer catalysts. Our finding might open a new door for the development of chiral DMAP‐N‐oxides for asymmetric acyl transfer reactions. A DMAP‐N‐oxide, featuring an α‐amino acid as the chiral source, was developed, synthesized and applied in asymmetric Steglich rearrangement. A series of O‐acylated azlactones afforded C‐acylated azlactones possessing a quaternary stereocenter in high yields (up to 97 % yield) and excellent enantioselectivities (up to 97 % ee).