the compounds of formula i in which neither r 1 nor r 2 is co 2 r 4 and x is of formula iia could be prepared from compounds of formula lxxix thus treatment of lxxix with sodium azide followed by acidification with dilute hydrochloric acid similar to that reviewed by kadaba synthesis 71 1973 would lead to formation of compounds of formula lxxx this is shown in scheme 39 str52 reactions requiring anhydrous conditions are performed in flame dried glassware and dry solvent was distilled prior to use following standard laboratory practices known to those skilled in the art of organic synthesis standard analytical equipment was used for sample purification and analyses a mixture of 11 6 g 100 mmol of indene and 75 ml dry tetrahydrofuran was stirred at 78 u00b0 c under nitrogen to this solution was added dropwise 62 5 ml 100 mmol of 1 6 m n butyllithium in hexane after stirring the mixture for 30 mins a solution of 22 1 g 110 mmol of 2 methoxybenzyl bromide in 100 ml dry tetrahydrofuran was added dropwise the mixture was stirred for an additional 3 hrs before warming to room temperature and quenching with water the aqueous mixture was extracted with 3 u00d7 100 ml ethyl acetate the organic layers were combined dried over anhydrous magnesium sulfate filtered and the solvent was removed the residue was hydrogenated over 500 mg of 10 palladium on carbon in absolute ethanol at 50 psi for 2 hrs the mixture was filtered and the solvent was removed the residue was purified by chromatography on silica gel using hexanes the solid obtained was 13 0 g 54 6 mmol 55.