2 42 2 49 m 1h 2 56 2 64 m 2h 3 24 3 48 m 2h 3 24 3 31 m 1h 3 42 3 48 m 1h 13 c nmr 75 mhz cdcl 3 u03b413 50 13 61 17 55 17 68 27 72 32 17 32 57 33 09 34 03 37 26 38 28 44 38 47 44 47 97 58 02 58 27 79 96 175 13 175 56 203 28 203 87 203 97 hreims data m z calcd for m h c 15 h 25 o 4 269 3566 obsd 269 3559 a mixture of ethyl methyl ketone 500 mg 6 93 mmol and nah 415 mg 10 39 mmol was treated with ethyl acrylate 693 mg 6 93 mmol at 0 u00b0 c in 5 ml dry toluene the solution was allowed to attain room temperature under stirring for 2 h the reaction mixture was acidified with 1 n hydrochloric acid extracted with ethyl acetate 3 u00d7 5 ml and washed with brine the combined organic layers was dried over anhydrous na 2 so 4 and concentrated under reduced pressure the crude product was purified by silica gel column chromatography hexane etoac 70 30 afforded 7 as a light yellow semisolid 480 mg 55 1 h nmr 300 mhz cdcl 3 u03b4.