Hydrolase-mediated resolution of the hemiacetal in 2-chromanols The impact of remote substitution

Hydrolase-catalysed dynamic kinetic resolutions of chroman-2-ol and 3-methyl chroman-2-ol can be effected with up to 88% conversion and 92% ee through the use of organic solvents. Extension to the resolution of the tolterodine precursor 1 proved more challenging. The presence of the remote phenyl substituent had a significant impact on the resolution and it was not possible to achieve high enantioselectivity together with efficient conversion from the focused panel of enzymes screened.