Enzymatic Synthesis of Noncanonical α‐Amino Acids Containing γ‐Tertiary Alcohols
Rui Zhang, Chenghua Zhang, Jiamu Tan, Yifan He, Dan Zhuo, Jingxuan Zhang, Zhenzhen Luo, Qiaoqiao Li, Jiaying Yao, Chang‐Qiang Ke, Chunping Tang, Yang Ye, Shijun He, Xiang Sheng, Cangsong Liao
Abstract
Abstract Noncanonical amino acids (ncAAs) containing tertiary alcohols are valuable as precursors of natural products and active pharmaceutical ingredients. However, the assembly of such ncAA scaffolds from simple material by C−C bond formation remains a challenging task due to the presence of multiple stereocenters and large steric hindrance. In this study, we present a novel solution to this problem through highly selective enzymatic decarboxylative aldol addition. This method allows for the streamlined assembly of multifunctionalized ncAAs with γ‐tertiary alcohols from readily available materials, such as L ‐aspartatic acid and isatins, vicinal diones and keto esters. The modularity of electrophiles furnished four classes of ncAAs with decent efficiency as well as excellent site and stereocontrol. Computational modeling was employed to gain detailed insight into the catalytic mechanism and to provide a rationale for the observed selectivities. The method offers a single‐step approach to producing multifunctionalized ncAAs, which can be directly utilized in peptide synthesis and bioactivity assessment.