Kinetic Resolution of Chiral Aminoalkenes

The efficient kinetic resolution of chiral aminoalkenes has been achieved utilizing the binaphtholate complexes (R) 38 Ln (Table 11.3) [52, 124]. Various chiral amino pentenes were kinetically resolved with resolution factors/(defined as f= x fefast/fesiow, where is the Curtin Hammett equilibrium constant between the two diastereomeric substrate/catalyst complexes and kfast/fesiow being the ratio between the faster and the slower reaction rate constant) as high as 19 and enantiomeric excess for recovered starting material reaching 80% ee at conversions dose to 50%. The 

5 disubstituted pyrrolidines were obtained in good to excellent trans diastereo selectivity, depending on the steric hindrance of the a substituent. Kinetic resolution of 84e using 1 mol% (R) 38a Lu gave enantiopure (S) 84e ( 99% ee) in 33% re isolated yield at 64% conversion [52]. 

Substrate Catalyst (h) Conversion (%) trans cis % ee of recovered starting material f 

Equation 11.13. Gold catalyzed dynamic kinetic resolution of aminoallenes [127]. 

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The binaphtholate complexes (R)-33 were successfully applied in the efficient kinetic resolution of chiral aminoalkenes (Table 5) [101,163,171]. Racemic aminopentenes can be kinetically resolved with resolution factors / as high as 19. The resolution factor value depends dramatically on the nature of the substituent R. Mechanistic studies have revealed that diminished efficiencies in the kinetic resolution of aminoalkenes with aliphatic substituents is caused by an unfavorable state of the Curtin-Hammett pre-equilibrium that favors the mismatching substrate-catalyst complex, whereas in the significantly more efficient kinetic resolutions of aryl-substituted aminoalkenes the matching substrate-catalyst complex predominates the pre-equilibrium [171]. 

The binaphtholate complexes (R)-63 were successfully applied in the efficient kinetic resolution of chiral aminoalkenes (Table 16) [67, 121, 122]. Racemic... 

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