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23rd July 2012 @ 00:37
START: 23/07/12 FINISH: 23/07/12 [b][u]Summary and Conclusion[/b][/u] Yb(OTf)3/THF catalyst solution: 36 mM. Substrate scale: 103 mg (to 0.02 M). Yb(OTf)3 loading: 5 mol%. Solvent: THF. Isolated yield: 51% (following chromatography). [b][u]Hazard and Risk Assessment[/b][/u] [data]4228[/data] [b][u]Previous Experiments[/b][/u] [blog]6069[/blog] [blog]5847[/blog] [blog]6094[/blog] [blog]6135[/blog] [blog]6109[/blog] [b][u]Chemical Information[/u][/b] [b]2-(3,4-dimethoxyphenyl)-N-(4-nitrobenzylidene)ethanamine[/b] - SMILES: O=[N+]([O-])C1=CC=C(/C=N/CCC2=CC(OC)=C(OC)C=C2)C=C1, InChI: InChI=1S/C17H18N2O4/c1-22-16-8-5-13(11-17(16)23-2)9-10-18-12-14-3-6-15(7-4-14)19(20)21/h3-8,11-12H,9-10H2,1-2H3/b18-12-, InChIKey: LMBMXYXQVBPKHJ-PDGQHHTCSA-N. [b]1-(6,7-dimethoxy-1-(4-nitrophenyl)-3,4-dihydroisoquinolin-2(1H)-yl)ethanone (KAB26-14) -[/b] SMILES: O=[N+]([O-])C1=CC=C(C2N(C(C)=O)CCC3=CC(OC)=C(OC)C=C32)C=C1, InChI: InChI=1S/C19H20N2O5/c1-12(22)20-9-8-14-10-17(25-2)18(26-3)11-16(14)19(20)13-4-6-15(7-5-13)21(23)24/h4-7,10-11,19H,8-9H2,1-3H3, InChIKey: OIFIJKJQAGAGKY-UHFFFAOYSA-N. [b][u]Procedure[/b][/u] [i]All THF was dried over 3 Å molecular sieves (1.5-2.5 mm) for >72 h[/i] [b]Catalyst Solution Preparation[/b] Yb(OTf)3 (113 mg, 0.182 mmol) was dissolved in THF (5.1 mL) to give a 36 mM solution. To a mixture of 3 Å molecular sieves in THF (16 mL) was dissolved MNR42-1 (103 mg, 0.328 mmol, 1 equiv.). The mixture was cooled in an acetone ice bath (-10 °C) before the addition of acetyl chloride (0.04 mL, 0.6 mmol, 1.7 equiv.) and 2,6-lutidine (0.06 mL, 0.5 mmol, 1.6 equiv.). Yb(OTf)3/THF (0.46 mL, 0.016 mmol, 0.05 equiv.) was added. The reaction mixture was allowed to warm to 25 °C and stirred under argon from 09:30. After 1.5 hours, the reaction mixture was diluted with EtOAc (20 mL). Saturated sodium bicarbonate solution was added (15 mL). The organic layer was separated. The aqueous layer was extracted with EtOAc (3 × 15 mL). The organic layers were combined, dried (MgSO4) and concentrated under reduced pressure before dry loaded onto a silica gel column. Column chromatography (60-65%, EtOAc/hexane, v/v) of the crude product yielded KAB26-15 as a yellow solid (59 mg, 51%). [b][u]Summary and Conclusion[/b][/u] Yb(OTf)3/THF catalyst solution: 36 mM. Substrate scale: 103 mg (to 0.02 M). Yb(OTf)3 loading: 5 mol%. Solvent: THF. Isolated yield: 51% (following chromatography). [b][u]References[/b][/u] [1] D. Bradley, G. Williams and M. Lawton, J. Org. Chem. [b]2010[/b], [i]75[/i], 8351. DOI: 10.1021/jo101589h [url=http://dx.doi.org/10.1021/jo101589h]Paper[/url]. [i][b]Abbreviations Used:[/b] EtOAc = ethyl acetate TLC = thin layer chromatography RM = reaction mixture MS = molecular sieves Soln = solution[/i] ------------------------------------------ NOTES ------------------------------------------
Attached Files
Scheme KAB26-15
Table KAB26-15