Enantiopure 3-methyl-3,4-dihydroisocoumarins and 3-methyl-1,2,3,4-tetrahydroisoquinolines via chemoenzymatic asymmetric transformations
A new divergent and asymmetric synthetic route has been developed for the production of enantiomerically pure isocoumarin and isoquinoline derivatives. Stereoselective formation of 2-(2-hydroxypropyl)benzonitriles has been identified as the key step. Rhizomucor miehei lipase has displayed from moderate to excellent selectivities in the acetylation of its (R)-enantiomers, while ADH-A from Rhodococcus ruber catalyzed the bioreduction of the corresponding ketones with excellent activities and stereopreferences. Enantiopure alcohols obtained in this manner have been used for the straightforward synthesis of a series of 3-methyl-3,4-dihydroisocoumarins and 3-methyl-1,2,3,4-tetrahydroisoquinolines with good overall yields.
- This article is part of the themed collection: Biocatalysis