One-pot stereoselective synthesis of chiral 1, 3-oxathiolane by Trichosporon laibachii lipase: Optimization by response surface methodology integrated a desirability function approach

The asymmetric synthesis of chiral 1,3-oxathiolan-5-ones has attracted a great deal of attention owing to their broad biological activities and importance as intermediates for a range of useful pharmaceuticals. However, the enantiomeric purity of desired enantiomer was moderate while maintaining high yield. Here, high enantiomerically pure chiral 1,3-oxathiolane intermediate was synthesized by cyclization-acetylation reaction in organic media using immobilized Trichosporon laibachii (T. laibachii) lipase with one-pot process. Response surface methodology (RSM) integrated a desirability function approach was used to study and optimize the reaction conditions. The effects of several reaction parameters (initial water content of reaction medium, lipase amount and reaction temperature) on enantiomeric excess (ee) and the conversion of benzoyl aldehyde (C) were evaluated. The enzyme activity as well as enantioselectivity was markedly influenced by the initial water content of reaction medium and reaction temperature. The maximum overall desirability (D) of 0.958 was achieved at initial water content of 0.46%, lipase amount of 4.58% and reaction temperature 43 °C. The corresponding maximum ee and C were 94.33% and 97.40%, respectively. A good correlation between the predicted and actual responses showed that the generated model could adequately predict ee and C.