Summary: | Herein, we report the preparation of enantiomerically pure forms of 2,3-dihydrobenzofuran-3-ol ( 1 ), chroman-4-ol ( 2 ), thiochroman-4-ol ( 3 ), 1-(furan-2-yl) ethanol ( 5 ) and 1-(thiophen-2-yl) ethanol ( 6 ), through a kinetic resolution catalysed by Candida antarctica lipase B /Na 2 CO 3 hydrolysis sequence in organic media. The (R) -furnished alcohols and the (S)- remained acetates are recovered enantiopures (ee >99%, E ≫ 200, Conv = 50%). Those ideal enzymatic kinetic resolution (EKRs) are well incorporated to the Mitsunobu inversion protocol in a one pot procedure to give (S)- heterocyclic acetates ( 1a–3a ) in good to high enantiomeric excess (88%–92% ee). Whilst, the (S)- heteroaromatic acetates ( 5a and 6a ) are given with moderate enantiomeric excess (51%–62% ee). All the (S)- acetates are given in good isolated chemical yields (>80%) allowing to overcome the maximum of 50% yield which could be usually reached in a regular kinetic resolution processes.
|