O=[C:2]1[N:7]([CH2:8][C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=2)[CH2:6][C:5](=O)[N:4]2[CH2:16][CH2:17][CH2:18][C:3]12[C:19](OCC)=[O:20].[H-].[Al+3].[Li+].[H-].[H-].[H-].O.[OH-].[Na+]>C1COCC1>[C:9]1([CH2:8][N:7]2[CH2:6][CH2:5][N:4]3[CH2:16][CH2:17][CH2:18][C:3]3([CH2:19][OH:20])[CH2:2]2)[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=1To a solution of ethyl 1,4-dioxo-2-(phenylmethyl)hexahydropyrrolo[1,2-a]pyrazine-8a(6H)-carboxylate (D65, 450 mg) in anhydrous THF (5 mL) under a Nitrogen atmosphere at 0° C., lithium aluminium hydride (1M in THF, 14 mL) was added dropwise. The resulting mixture was stirred at 0° C. for 10 minutes, then allowed to reach rt and stirred at this temperature for 45 minutes. It was then heated at reflux temperature for 3.5 hours and then allowed to cool to r.t. Water (540 microL), NaOH (1M solution, 540 microL) and water (1.6 mL) were then added to the solution and the formation of a white precipitate was observed. The suspension was stirred at rt for 30-40 minutes then filtered over a Gooch funnel. The organic filtrate was dried and concentrated in vacuo to a residue which was purified by flash chromatography (DCM/MeOH from 100/0 to 90:10) to give the desired compound (162 mg) as orange oil.
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