Divergent Protein Engineering of Transaminase for the Synthesis of Chiral Rivastigmine and Apremilast Precursors

Comprehensive Summary The implementation of divergent protein engineering on the natural transaminase Vf‐ω‐TA led to the development of two effective mutants (M2 and M8), enabling the enzymatic synthesis of chiral amine precursors of Rivastigmine and Apremilast, respectively. The evolution of the enzymes was guided by crystal structures and a focused mutagenesis strategy, allowing them to effectively address the challenging ketone substrates with significant steric hindrance. Under the optimized reaction parameters, transamination proceeded smoothly in good conversions and with perfect stereochemical control (> 99% ee). These processes utilize inexpensive α‐methylbenzylamine as an amine donor and avoid the continuous acetone removal and costly LDH/GDH/NADH systems. Wide‐type transaminase Vf‐ω‐TA was rationally engineered in a divergent way to accommodate non‐natural bulky ketones substrates, facilitating the enzymatic synthesis of chiral amine precursors of Rivastigmine and Apremilast in good yields and > 99% ee.