the mixture was stirred at rt for 24 h filtered and the filtrate concentrated under reduced pressure the residue was partitioned between dichloromethane and brine organic layer was washed with brine followed by 0 5 m kbr dried na 2 so 4 and evaporated to a syrup flash silica gel column chromatography using 15 30 gradient of acetone in hexanes yielded product 6 as a colorless foam 6 g 81 1 h nmr u03b4 7 43 m 5h phenyl 5 60 d 1h j nh 2 80 8 nh 5 44 d j 4 3 3 2 1h h4 5 40 dd j 3 4 30 2 j 3 2 10 8 1h h3 5 19 s 2h ch 2 ph 4 80 d j 1 2 8 0 1h h1 4 23 m 2h ch 2 3 99 m 3h h2 h6 3 56 m 1h h5 2 43 t j 7 2 2h ch 2 2 22 s 3h ac 2 12 s 3h ac 2 08 s 3h ac 2 03 s 3h ac 1 64 m 4h 2 u00d7 ch 2 1 33 br m 14h 7 u00d7 ch 2 ms esi u2212 m z 634 5 m u2212 h u2212 conjugate 6 2 g 3 14 mmol was dissolved in ethanol 50 ml and 5 pd c 0 3 g was added the reaction mixture was hydrogenated overnight at 45 psi h 2 the catalyst was filtered off and the filtrate evaporated to dryness to afford pure 7 1 7 g quantitative as a white foam 1 h nmr u03b4 5 73 d 1h j nh 2 80 4 nh 5 44 d j 4 3 3 0 1h h4 5 40 dd j 3 4 3 0.