p 2 o 5 prior to use all glassware was oven dried prior to use lipase catalyzed transesterifications a homogenous mixture of alcohol 5 mmol and u03b2 ketoester 20 mmol was treated with 10 w w of alcohol of the catalyst and swirled in a 50 ml flask connected to a b u00fcchi rotavapor at 40 u00b0 c and 10 torr for entries 9 12 fig2 the ratio was 1 2 to 1 between alcohol and u03b2 ketoester respectively after 8 hours 20 ml of ch 2 cl 2 was added and the polymer supported lipase removed by filtration the solvent was removed under reduced pressure and the crude product purified by silica gel column chromatography with increasing amounts of etoac in hexane the spectral data for 17 18 19 and 21 were in accordance with those reported in literature j g gilbert et al j org chem 1988 53 449 d f taber et al j org chem 1985 50 3618 c mottet et al j org chem 1999 64 138 b s balaji et al j chem soc chem commun 1996 707 m p doyle et al j am chem soc 1995 117 5763 lipase catalyzed parallel reactions vials containing different mixtures of alcohols 1 mmol and u03b2 ketoesters 8 mmol together with 10 mg of calb were placed in a vaccum oven at 40 u00b0 c and 10 torr after 24 hours 3 ml of ch 2 cl 2 was added to each.