Abstract

Chiral α-amino carbonyl compounds are versatile building blocks in organic synthesis. Catalytic asymmetric N–H bond insertion of metal carbenes, typically derived from α-diazo carbonyl compounds, serves as an attractive method for the synthesis of these compounds. Recently, α-carbonyl sulfonium ylides have been developed as an important safe substitute for α-diazo carbonyl compounds and demonstrated to be useful in a range of asymmetric cycloaddition and insertion reactions. The potential to allow organocatalysis for these reactions also renders them to be complementary to the metal carbene chemistry.1,2 However, the instability and/or harsh conditions for the synthesis of α-carbonyl sulfonium ylides limited their broad applications. In this context, direct use of the easily accessible and stable α-carbonyl sulfonium salts provides an alternative solution. This new protocol features an improved reaction scope and broad functional group compatibility. Mild and stereoselective intermolecular C–N bond formation was achieved through in situ generated chiral ion pairs via dynamic kinetic resolution. This discovery also sheds light on a general strategy of enantioselective α-functionalization of carbonyl compounds. 

Reference：

1. Guo, W.; Luo, Y.; Sung, H. H.-Y.; Williams, I. D.; Li, P.; Sun, J. J. Am. Chem. Soc. 2020, 142, 14384 – 14390.
2. Guo, W.; Wang, M.; Han, Z.; Huang, H.; Sun, J. Chem. Sci., 2021, 12, 11191 – 11196.