Microbial reduction of 2-keto acetals as a biocatalytic approach to the enantioselective synthesis of optically active 2-hydroxy acetals
摘要:
The reduction of the 2-keto acetals 1a and 1b by means of different microorganisms constitutes the biocatalytic access to optically active (46 to 100% ee) 2-hydroxy acetals, (S)-2a or (R)- and (S)-2b, representative compounds of a class of synthetically useful chiral building blocks.
Asymmetric reduction of α-keto acetals with potassium 9-O-(1,2-isopropylidene-5-deoxy-D-xylofuranosyl)-9-boratabicyclo[3.3.1]nonane. Enantioselective synthesis of α-hydroxy acetals with high optical purities
摘要:
Asymmetric reduction of alpha-keto acetals with a chiral borohydride, potassiun 9-O-(1,2-isopropylidene-5-deoxy-alpha-D-xylofuranosyl)-9-boratabicyclo[3.3.1]nonane in THF at -78 degrees C provided the corresponding alpha-hydroxy acetals with 87-99% ee.
We report the first enzyme-catalysed kinetic resolution of epoxy enol esters. The lipase-promoted hydrolysis of these compounds provided alpha-hydroxyketones or alpha-hydroxyaldehydes (arising from the spontaneous rearrangement of the epoxy enols) and the residual esters with moderate to good enantioselectivity (E up to 100). (c) 2006 Elsevier Ltd. All rights reserved.