to the deuterium lock signal from the sample solvent unless otherwise stated all mass spectrum were performed using electron impact el 70 ev conditions unless otherwise indicated chromatography refers to column chromatography performed using 32 63 u03bcm silica gel and executed under nitrogen pressure flash chromatography conditions high pressure liquid chromatography hplc was performed on hewlett packard 1100 series hplc a inertsil 5 u03bc c8 150 u00d7 4 6 mm metachem technologies inc was used for hplc analysis mobile phase 1100 ml acetonitrile 1000 ml water 2 ml h 3 po 4 2 ml tea flow rate of 1 0 ml min detector uv 250 nm injector 10 ul column temperature 35 c ethyl succinyl chloride ethyl 3 chloroformyl proprionate 57 ml 381 mmol 2 5 molar equivalents was dissolved in anhydrous dichloromethane 610 ml under a nitrogen atmosphere in the temperature range 15 25 u00b0 c sodium hydroxide pellets 3 1 g 76 mmol 0 5 molar equivalents were then added and the resultant mixture stirred well under nitrogen for 75 min at 15 25 u00b0 c this mixture was then held for use in part b magnesium bromide diethyl etherate adduct mgbr 2 et 2 o 82 3 g 320 mmol 2 1 molar ratio was stirred into anhydrous dichloromethane 1200 ml under a nitrogen atmosphere in the temperature range 15 25 u00b0 c the nitrogen atmosphere was maintained for the entire procedure triethylamine 54 ml 3 81 mmol 2 5 molar ratio was added and the resultant suspension was cooled to 6.