Chemoenzymatic Dynamic Kinetic Resolution of Axially Chiral Allenes

Abstract

At the palladium: Dimeric palladium bromide complexes bearing monodentate N-heterocyclic carbene ligands have been identified as efficient catalysts for the chemoselective racemization of axially chiral allenyl alcohols. In combination with porcine pancreatic lipase as biocatalyst, a dynamic kinetic resolution has been developed, giving access to optically active allenes in good yield and high enantiomeric purity (see scheme).

6.08 Acylation-Type Reactions: Synthesis of Esters via Acyl Transfer

“…Deska and Bäckvall introduced the first DKR of allenols mediated by a palladium complex in combination with the enzyme porcine pancreatic lipase (PPL). 156 The yields are good and the obtained ees ranged from 66 to 89% ( Table 50). Enantioenrichment of the allenols can be achieved by enzymatic hydrolysis (ee¼ 99%; yield ¼ 91% for 411).…”

Lipases: Valuable catalysts for dynamic kinetic resolutions

“…17) (Deska et al, 2010). The resulting esters were obtained with moderate optical purity, which was increased by a subsequent hydrolysis step catalyzed by the same enzyme.…”

An Efficient Dynamic Kinetic Resolution of N‐Heterocyclic 1,2‐Amino Alcohols

“…entries [11][12][13]. Substrate 1f seemed to be within the optimal size range for all three biocatalysts screened since good enantioselectivity was observed for all of them ( Table 2, entries 14-16).…”