further defined by reference to the following examples describing in detail the process and compositions of the invention it will be apparent to those skilled in the art that many modifications both to materials and methods may be practiced without departing from the scope of the invention column xterra rp8 3 5 u03bc 150 u00d7 4 6 mm waters p n 186000443 or equivalent a 60 suspension of sodium hydride in mineral oil 34 4 g 1 43 mol was added to dry toluene 3000 ml under a nitrogen atmosphere cooled and stirred at 0 5 u00b0 c for 15 20 minutes triethyl phosphonoacetate 257 1 g 1 148 mol was added dropwise at 0 5 u00b0 c and stirred for 2 hr at room temperature 1 2 6 7 tetrahydro 8h indeno 5 4 b furan 8 one 100 0 g 0 5740 mol was added and the reaction mixture was heated to 90 100 u00b0 c and stirred under a nitrogen atmosphere for 15 18 hr the reaction was monitored by hplc after completion of the reaction the mixture was cooled and water was added slowly with stirring the organic layer was separated washed with brine and concentrated under vacuum at 50 60 u00b0 c to leave crude product yield 80 85 purity 92 95 by hplc a mixture of compound of formula ii ethyl 2 1 2 6 7 tetrahydro 8h indeno.