Parallel Interconnected Kinetic Asymmetric Transformations (PIKAT) Applied to the Concurrent Chiral Synthesis of sec-Alcohols and Sulfoxides

FABRICIO R. BISOGNO; ANA RIOZ-MARTÍNEZ; CRISTINA RODRÍGUEZ; GONZALO DE GONZALO; IVÁN LAVANDERA; DANIEL E. TORRES PAZMIÑO; MARCO W. FRAAIJE; VICENTE GOTOR

Berna, Suiza

Congreso; BIOTRANS 2009; 2009

  In nature, a huge number of chemically interconnected processes concurrently take place and the products are shared by different metabolic routes, forming a complex and effective metabolic network. Taking advantage of catalysts isolated or derived from nature, several (bio)catalytic strategies have been developed in order to successfully achieve the resolution of stereoisomers such as parallel kinetic resolution,1 PKR (Scheme 1A) or dynamic kinetic asymmetric transformation,2 DYKAT (Scheme 1B) in order to maximize both product yield and enantiopurity. In an attempt to mimic natural processes, concurrent catalysis is recently gaining more relevance applied to the synthesis of enantioenriched derivatives. In the ideal case, all the steps should work at comparable rates and, most importantly, no interference should exist among all processes involved.3  Herein we describe a novel concept which allows the concurrent preparation of enantioenriched derivatives in a strict parallel fashion minimizing the quantity of reagents employed and maximizing the redox economy of the process by coupling two asymmetric transformations: a kinetic oxidative resolution catalyzed by an ADH plus a desymmetrization oxidation catalyzed by a BVMO (Scheme 1C). In this particular case, two asymmetric transformations are truly occurring in a parallel way. If the reaction conditions are not appropriate, even for only one of the processes, both reactions will not be completed due to the fact that are connected by a linker (in this case the nicotinamide coenzyme) which is the key to the whole system outcome. Considering the above mentioned features, this process  can be named Parallel Interconnected Kinetic Asymmetric Transformation (PIKAT).4