HYDROLYTIC ENZYMES IN THE SYNTHESIS OF CARBA-SUGARS - APPLICATION OF THE LIPASE FROM PSEUDOMONAS-FRAGI

Pig liver esterase-catalysed hydrolysis of do-2-methoxycarbonyl-7-oxab icyclo[2.2.1]hept-5-ene 1a provides -)-endo-7-oxabicyclo[2.2.1]hept-5- ene-2-carboxylic acid 1b and do-2-methoxycarbonyl-7-oxabicyclo[2.2.1]h ept-5-ene 1a in 36 and 57% ee, respectively. Transesterification betwe en hydroxy-4,8-dioxatricyclo[4.2.1.0(3,7)]nonan-5-one 2a and vinyl ace tate catalysed by the lipase from Pseudomonas fragi gives the acetate (-)-2b and alcohol (+)-2a in 91 and 94% ee, respectively, Optically pu re acetate (-)-2b is obtained after removal of contaminating racemate from the impure acetate by crystallisation of(-)-2b of 91% ee (EtOH).