Difficult substrates in the R-hydroxynitrile lyase catalyzed hydrocyanation reaction: application of the mass transfer limitation principle in a two-phase system

The application of a number of new and/or difficult substrates in the catalyzed hydrocyanation reaction by R-hydroxy nitrile lyase from almonds is described. By using an aqueous-organic two-phase system and increasing the rate of the enzymatic reaction relative re, the mass transfer rate, the enantiomeric purity was improved. By fine tuning the reaction parameters (temperature, pH. and the amount of enzyme) the hydrocyanation reaction was optimized for all substrates. The general principles described here can also be applied to optimize the reaction conditions: for other substrates. (C) 2001 Elsevier Science Ltd. All rights reserved.