Exquisite use of Selenoesters as Recyclable Acyl Donors for Lipases-catalyzed Kinetic Resolution

Lipase-catalyzed enantioselective synthetic reactions employing enol esters, activated esters, anhydrides, and oximes as acyl donors is a well-consolidated strategy towards enantiopure compounds. However, lipases can also cleave the C-S bond of thioesters, proving that other classes of substances can be used as acyl donors in lipase-catalyzed transformations. Herein we describe the application of selenoesters as a new class of acyl donors in enzymatic kinetic resolution of chiral alcohols. A series of selenoesters was successfully employed in the resolution of chiral primary and secondary alcohols, demonstrating that lipases can also cleave the C-Se bond. Assays using selenoesters as acyl donors in lipase-catalyzed reactions furnished enantiopure compounds (e.e.>99 %) and enantiomeric ratio (E>200). We also observed that the enzymatic reaction is accelerated in an oxygen atmosphere and performing a preparative scale reaction could demonstrate how simple and easy the purification process is to recover the diselenide formed during the resolution.