Total Synthesis and Biological Evaluation of ( )-9-Deoxy- Englerin A

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1 Supporting Information Total Synthesis and Biological Evaluation of ( )-9-Deoxy- Englerin A Dmitry B. Ushakov, Vaidotas Navickas, Markus Ströbele, Cäcilia Maichle-Mössmer, Florenz Sasse, and Martin E. Maier*, Institut für rganische Chemie, Universität Tübingen, Auf der Morgenstelle 8, Tübingen, Germany Abteilung für Festkörperchemie und Theoretische Anorganische Chemie, Institut für Anorganische Chemie, Universität Tübingen, b dem immelreich 7, 7207 Tübingen, Germany Institut für Anorganische Chemie, Universität Tübingen, Auf der Morgenstelle 8, Tübingen, Germany Abteilung Chemische Biologie elmholtz-zentrum für Infektionsforschung, Inhoffenstrasse 7, 382 Braunschweig, Germany martin.e.maier@uni-tuebingen.de Contents Experimental details... S2 Copies of NMR spectra... S S

2 Experimental section General. Unless otherwise noted, all reactions were performed in oven-dried glassware. All solvents used in the reactions were purified before use. Dry diethyl ether, tetrahydrofuran, and toluene were distilled from sodium and benzophenone, whereas dry C 2 Cl 2, dimethylformamide, methanol, ethyl acetate, benzene, and triethylamine were distilled from Ca 2. Petroleum ether with a boiling range of 0 60 C was used. Reactions were generally run under nitrogen atmosphere. All commercially available compounds (Acros, Aldrich, Fluka, Merck) were used without purification. and 3 C NMR: Bruker Avance 00, spectra were recorded at 295 K in CDCl 3 ; chemical shifts are calibrated to the residual proton and carbon resonance of the solvent: CDCl 3 ( 7.25, 3 C ). RMS (FT-ICR): Bruker Daltonic APEX 2 with electron spray ionization (ESI). Analytical LC-MS: P 00 Series connected with an ESI MS detector Agilent G96C, positive mode with fragmentor voltage of 0 ev, column: Nucleosil 00-5, C-8 D, 5 mm, 70 3 µm Machery Nagel, eluent: NaCl solution (5 mm)/acetonitrile, gradient: min with % acetonitrile, flow: 0.5 ml min. Flash chromatography: J. T. Baker silica gel 3 60 µm. Thin-layer chromatography Machery-Nagel Polygram Sil G/UV 25. ptical rotations: JASC Polarimeter P-020, sodium D line (589 nm), c = g per 00 ml. The azulene system was used for atom numbering of bi- or tricyclic compounds: 8a azulene guaiane vinylmgbr, TF ' 2' 2 ( )-isopulegone (2) 80 C to rt (92%) 0 5 (R,2S,5R)-5-Methyl-2-(prop--en-2-yl)--vinylcyclohexanol (0). Freshly prepared vinylmagnesium bromide 2 (250 ml,.7m solution in TF, 0.2 mol) was added dropwise to a stirred solution of ketone 3 2 (7.0 g, 0.33 mol) in TF (300 ml) at 80 C. The reaction mixture was allowed to warm to room temperature within h and quenched with saturated N Cl solution (50 ml), diluted with water (200 ml), and extracted with diethyl ether (3 00 ml). The combined organic layers were washed with saturated NaCl solution (2 00 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was distilled at low pressure (b.p C, mbar) to give alcohol 0 as a colorless oil (55.7 g, 92%). R f = 0.69 (petroleum ether/etac, 9:); [α] 20 D = +7.2 (c 2.9, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.86 (d, Gottlieb,. E.; Kotlyar, V.; Nudelman, A. J. rg. Chem. 997, 62, Vinylmagnesium bromide:,2-dibromethane (72 ml, 0.80 mol) was added dropwise ( h) to a stirred solution of K (60 g,.05 mol) in ethanol (00 ml) at 0 C. The resulting vinyl bromide was distilled from the reaction mixture (b.p. 6 C) through a Vigreux column (30 cm) and collected in a nitrogen cooled flask. Distillation over CaCl 2 (2 times) gave vinyl bromide (60 g, 70%) as a colorless liquid. Vinylbromide should be stored at 20 C and handled in a well ventilated hood. A solution of vinyl bromide (2.9 g, 2 mmol) in TF (50 ml) was added dropwise to a suspension of magnesium turnings (2.9 g, 30 mmol) in TF (0 ml), activated with a single iodine crystal, maintaining the temperature at 38 C. After complete addition of vinyl bromide, the reaction mixture was stirred for h at 0 C. The concentration was found to be.7m in TF by titration of a TF solution of menthol in presence of,0- phenantroline. 3 Moreira, J. A.; Corrêa, A. G. Tetrahedron: Asymmetry 2003,, S2

3 J = 6.6 z, 3, 5-C 3 ), (m,, -),.0 (ddd, J =.0, 2.2, 2.0 z,, 6-),.7 (ddd, J = 3.2, 6., 3.6 z,, 3-),.6 (ddd, J = 3.7, 3.3, 2.3 z,, 6-),.7 (s, 3, 2 - C 3 ), (m,, 3-, -, 5-, ),.98 (dd, J = 3.0, 3.3 z,, 2-),.73 (s,, - ),.87 (s,, -),.96 (dd, J = 0.7,.3 z,, C 2 vinyl), 5.6 (dd, J = 7.2,. z,, C 2 vinyl), 5.86 (dd, J = 7.0, 0.7 z,, C vinyl); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 22.2 (5-C 3 ), 25.7 (2 -C 3 ), 27. (C-5, C-3), 3.8 (C-), 6.5 (C-6), 52.0 (C-2), 73.2 (C-), 0.6 (C 2 vinyl),.7 (C- ), 6.2 (C vinyl), 8. (C-2 ); RMS (ESI): [M+Na] + calcd for C 2 20 Na , found K, TF 8-crown-6 ether reflux (89%) (9R,E)-5,9-Dimethylcyclodec-5-enone (9). A solution of alcohol 0 (26.7 g, 0.5 mol) and 8- crown-6 ether (3.9 g, 0.05 mol) in abs. TF (00 ml) was added to a stirred suspension of K (7.8 g, 0.5 mol) in TF (250 ml). The resulting mixture was stirred under reflux for 2 h. Then the reaction mixture was quenched with ethanol (30 ml) at 78 C, diluted with water (300 ml) and extracted with diethyl ether (3 00 ml). The combined organic layers were washed with saturated NaCl solution (2 00 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was distilled at low pressure (55 60 C, 0 2 mbar) to give ketone 9 as a colorless oil (23.9 g, 89%). R f = 0.59 (petroleum ether/etac, 9:); [α] 20 D = +2.9 (c.0, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.92 (d, J = 6.8 z, 3, 9-C 3 ),.7.23 (m, ),.3 (s, 3, 5-C 3 ), (m, 2), (m, ), (m, 6), (m, 2), (m, ), (m,, 6-); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 5.9 (5-C 3 ), 2.8 (9-C 3 ), 25.8, 27.3 (C 2 ), 28.8 (C-9), 37.3,.3, 3., 53.3 (C 2 ), 26. (C-6), 38.0 (C-5), (C=); RMS (ESI): [M+Na] + calcd for C 2 20 Na , found mcpba C 5 2 Cl 2 (83%) (R,7R,0R)-,7-Dimethyl--oxa-bicyclo[8..0]undecan-5-one (3). mcpba (.5 g, 7.0 mmol, 70 75%) was added to a stirred solution of ketone 9 (7.0 g, 39 mmol) in C 2 Cl 2 (00 ml) and the mixture stirred overnight at ambient temperature. The reaction mixture was quenched with saturated Na 2 S 2 3 solution (00 ml) and stirred for additional h. The organic layer was separated and washed with saturated NaC 3 solution (2 00 ml), water (00 ml), saturated NaCl solution (00 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 5:) to give epoxide 3 (6.3 g, 83%) as white crystals (m.p C). R f = 0.2 (petroleum ether/etac, 9:); [α] 20 D = 0. (c.29, Me); NMR (00 Mz, CDCl 3 ): δ[] = (ddd, J = 3.7, 3.7, 3.3 z,, 2-), 0.96 (d, J = 7. z, 3, 7-C 3 ),.5 (s, 3, -C 3 ),.25.5 (m, 2, 8-, 9-), (m,, 3-), (m, 2, 8-, 9-), (m, 2, 2-, 3-), (m,, -, 6-, 7-), 2.56 (dd, J = 7.5, 0.3 z,, 6-), 2.63 (dd, J = 7.5, 0.9 z,, 0-); 3 C-NMR (00 Mz, CDCl 3 ): δ[] = 6. (-C 3 ), 20.2 (C-3), 23. (7-C 3 ), 26. (C-9), 28.8 (C-7), 35.9 (C-8), 0.5 (C-2), 3.2 (C-), 52.3 (C-6), 6.5 (C-), 63.2 (C-0), 20.3 (C=); RMS (ESI): [M+Na] + calcd for C Na , found S3

4 Na, TF reflux (90%) (R,R,R,8aS)--ydroxy-,-dimethyl-octahydroazulen-(2)-one (7) and (R,R,R,8S,8aS)-,-Dimethyldecahydro-,8-epoxyazulen-8-ol (6). A solution of epoxy ketone 3 (7.0 g, 35.7 mmol) in TF (50 ml) was added to the suspension of Na (6.0 g, 50.0 mmol, 60% dispersed in mineral oil) in TF (200 ml) and stirred under reflux for h. Then the reaction mixture was cooled to 0 C and carefully quenched with saturated N Cl solution (50 ml). The mixture was diluted with water (00 ml) and extracted with diethyl ether (3 50 ml). The combined organic layers were washed with M Cl solution (50 ml), water (50 ml), saturated NaCl solution (50 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 9:) to give an inseparable mixture of ketone 7 and hemiketal 6 (7/6 = 30:70) which was introduced in next step without further purification (6.0 g, 90%). LDA, TF 80 C, 2 h (20%) (80%) (S,R,6R,8aR)--ydroxy-,6-dimethyl-octahydroazulen-()-one (). A freshly prepared solution of LDA in TF (.0 ml, 0.5M, 0.50 mmol) was added dropwise to a solution of epoxy ketone 3 (25 mg, 0.3 mmol) in TF ( ml) at 80 C followed by stirring of the mixture for 2 h at the same temperature. The reaction mixture was quenched with saturated N Cl solution (0 ml) and extracted with diethyl ether (3 0 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 9:) to give a mixture of ketone 7 / hemiketal 6 ( mg, 20%) and ketone (2 mg, 80%). R f = 0.8 (petroleum ether/etac, :); [α] 20 D = 6.8 (c 0.28, C 2 Cl 2 ); NMR (00 Mz, CDCl 3 ): δ[] = 0.83 (dddd, J = 3., 3., 2.0,.3 z,, 8-), 0.97 (d, J = 6.6 z, 3, 6-),.2.20 (m,, 7- ),.8 (s, 3, -C 3 ),.5.5 (m,, 2-), (m, 3, 2-, 6-, ), (m, 2, 3-, 8-), (m,, 7-), (m, 2, 3-, 8a-), 2.32 (ddd, J = 0.2, 2.8,.8 z,, 5-), 2.2 (dd, J =., 0.2 z,, 5-), 3.2 (ddd, J = 9., 9., 7. z,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 2.8 (C-3), 23.6 (-C 3 ), 2. (-C 3 ), 27.5 (C-8), 3. (C-6), 38.6 (C-2), 38.6 (C-7), 52.2 (C-5), 52.3 (C-8a), 55. (C-), 82. (C-), 23.2 (C-); RMS (ESI): [M+Na] + calcd for C Na , found NaB 7 Me, rt h (9%) 5 C 3 The order of addition (base to ketone or ketone to base) did not influence the enolate formation. In both experiments the respective product ratios were the same. S

5 (R,R,R,8R,8aS)-,-Dimethyldecahydroazulene-,8-diol (5). NaB (50 mg,.30 mmol) was added to a solution of ketone 7 (70 mg, 0.87 mmol) in a TF/Me mixture (0 ml/ ml) at 78 C. The resulting mixture was allowed to warm to ambient temperature and stirred for h at room temperature. Then the reaction mixture was cooled to 0 C and carefully quenched with water (0 ml). The mixture was extracted with diethyl ether (3 20 ml). The combined organic layers were washed with water (20 ml), saturated NaCl solution (20 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, :) to give diol 5 (55 mg, 9%) as a colorleess oil. R f = 0.3 (petroleum ether/etac, :); [α] 20 D =.0 (c 2.35, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.99 (d, J = 6.3 z, 3, - C 3 ),.05 (ddd, J = 2.3, 2.3, 5.8 z,, 2-),.7 (s, 3, -C 3 ), (m,, 3-),.0 (dddd, J =.7, 7.6, 3.8, 3.7 z,, 6-),.6.60 (m, 3, -, 5-, 7-),.65.9 (m, 6, 2-, 3-, 5-, 6-, 7-, 8a-), 2.32 (ddd, J =.2,.2, 7. z,, -), 3.9 (dd, J = 6.6, 3.0 z,, 8-),.6 (br s,, ); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 7. (C-6), 9.5 (- C 3 ), 30.2 (C-7), 3. (C-3), 32.2 (-C 3 ), 3.6 (C-2), 36.7 (C-5), 39.7 (C-), 5. (C-, C-8a), 7.7 (C-8), 75.5 (C-); RMS (ESI): [M+Na] + calcd for C Na , found (Piv) 2, Sc(Tf) 3 ( mol%) C 3 CN, 0 C Piv 8 + Piv (37%) 7 (6%) (R,R,R,8aS)-,-Dimethyl-8-oxo-decahydroazulen--yl-pivalate (7) and (3R,S,R,8R,8aR)-3,8-Dimethyldecahydro-,8-epoxyazulen--yl pivalate (8). Pivalic anhydride (6 ml, 79. mmol) was added dropwise to a stirred solution of 7 and 6 mixture (.3 g, 2.9 mmol) in dry acetonitrile (90 ml) at 0 C, followed by addition of Sc(Tf) 3 (0. g, 0.2 mmol) dissolved in acetonitrile ( ml) at the same temperature. The resulting mixture was stirred overnight at 0 C, quenched with saturated NaC 3 solution (50 ml) and extracted with diethyl ether (3 50 ml). The combined organic extracts were washed with saturated NaCl solution (50 ml), dried over MgS, filtered, and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 25:) to give pivalic ketone 7 (3.7 g, 6%) and protected hemiketal 8 (2.3 g, 37%) as colorless oils. Pivalic ketone 7: R f = 0.65 (Petroleum ether/etac, :); [α] 20 D = (c.0, C 2 Cl 2 ); NMR (00 Mz, CDCl 3 ): δ[] =.0 (d, J = 6. z, 3, -C 3 ),.08 (s, 9, (C 3 ) 3 ),.6.26 (m,, 2-),. (s, 3, -C 3 ), (m, 5, 2 3-, 5-, 2 6-), (m, 2, -, 2- ), (m, 3, 5-, 7-, 8a-), 2.57 (ddd, J =.7,.7, 3.3 z,, 7-), 2.95 (ddd, J =.2,.2, 7. z,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 9.9 (-C 3 ), 2.2 (C-6), 26.2 (-C 3 ), 27. (C(C 3 ) 3 ), 29. (C-3), 35.3 (C-5), 35. (C-2), 39.2 (C-), 39.6 (C(C 3 ) 3 ),.5 (C-7), 9. (C-), 6.3 (C-8a), 86. (C-), 77.7 (C= ester), 22. (C= ketone). RMS (ESI): [M+Na] + calcd for C Na , found emiketal pivalate 8: R f = 0.75 (Petroleum ether/etac, :); NMR (00 Mz, CDCl 3 ): δ = 0.99 (d, J = 6. z, 3, -C 3 ),.5 (s, 9, C(C 3 ) 3 ),.26 (s, 3, -C 3 ),.0.68 (m, 7, 5-, 2-), (m, 2), (m, 2, 3-), (ddd, J =.9,.7, 6.2 z, ), 2.6 (dd, J = 3.8, 8.2 z,, -), 2.79 (ddd, J = 3.6, 8.6, 8.6 z,, 8a-); 3 C NMR (00 Mz, CDCl 3 ): δ = 7.9 (-C 3 ), 20.9 (C-6), 25.0 (-C 3 ), 27.0 (C(C 3 ) 3 ), 27.9 (C-3), 28.9 (C-5), 3.8 (C-2), 33.7 (C-), 38.5 (C(C 3 ) 3 ),. (C-7), 5.5 (C-8a), 62.5 (C-), 82. (C-), 0.0 (C- 8), 76.0 (C(C 3 ) 3 ); RMS (ESI): [M+Na] + calcd for C Na , found Recycling of 7+6 via pivalic ester cleavage: K 2 C 3 (.20 g, 30. mmol) was added to a stirred solution of ester 8 (2.85 g, 0.2 mmol) in methanol (70 ml). The resulting mixture was stirred for 0 h at 60 C, quenched with water (00 ml) and extracted with diethyl ether (3 00 ml). The 8 S5

6 combined organic layers were washed with saturated NaCl solution (2 00 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 5:) to give alcohol 7+6 (.83 g, 92%) as a colorless oil. Piv LDA, ZnCl 2 acetone TF, 78 C (83%) Piv 8 2' 7 9 (R,R,R,7S,8aS)-7-(2-ydroxypropan-2-yl)-,-dimethyl-8-oxodecahydroazulen--yl pivalate (9). A solution of ketone 7 (200 mg, 0.7 mmol) in TF (6 ml) was added dropwise to freshly prepared LDA (.7 ml, 2. mmol, 0.5M solution in TF) at 5 C. The resulting mixture was stirred for h before ZnCl 2 (0.85 ml, 0.85 mmol, M solution in diethyl ether) was added dropwise at 78 C, followed by addition of acetone (0.6 ml, 8.7 mmol). After 30 min the reaction mixture was quenched with saturated N Cl solution (5 ml), diluted with water (5 ml) and extracted with diethyl ether (3 20 ml). The combined organic layers were washed with saturated NaCl solution (20 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 5:) to give aldol product 9 (93 mg, 83%) as a colorless oil. R f = 0.53 (Petroleum ether/etac, 2:); [α] 20 D = +50. (c 0.76, Me); NMR (00 Mz, CDCl 3 ): δ[] =.06 (d, J = 6.6 z, 3, -C 3 ),.2 (s, 9, CC(C 3 ) 3 ),.2 (s, 6, 2 2 -C 3 ), (m,, 2-),.6.89 (m, 8, -C 3, 2 3-, -, 5-, 2 6-), (m,, 2-), (m,, -), (m, 2, 8a-, 5- ), 2.58 (dd, J = 2., 2.0 z,, 7-), 2.95 (ddd, J = 2.8,.3, 6. z,, -), 3.87 (br. s,, 2 -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 9.8 (-C 3 ), 22.9 (C-6), 27. (CC(C 3 ) 3 ), 27. (2 -C 3 ), 27.6 (-C 3 ), 29.0 (2 -C 3 ), 30.2 (C-3), 3. (C-5), 35.7 (C-2), 39.0 (C-), 39.6 (CC(C 3 ) 3 ), 50. (C-), 56.9 (C-7), 62.5 (C-8a), 7.9 (C-2 ), 85.3 (C-), 77.7 (C= ester), 27. (C= ketone); RMS (ESI): [M+Na] + calcd for C 20 3 Na , found Piv Burgess reagent PhC 3, 0 C (00%) Piv 9 20 (R,R,R,7R,8aS)-,-Dimethyl-8-oxo-7-(prop--en-2-yl)decahydroazulen--yl pivalate (20). Burgess reagent 5 (2 mg, 0.77 mmol) was added to a stirred solution of alcohol 9 (5 mg, 0.0 mmol) in abs. toluene (3 ml) and the mixture stirred at 0 C for 5 min. After cooling, the solvent was evaporated and the residue purified by flash chromatography (petroleum ether/etac, 5:) providing alkene 20 ( mg, quant.) as a colorless oil. R f = 0.56 (petroleum ether/etac, 9:); [α] 20 D = (c 2.7, Me); NMR (00 Mz, CDCl 3 ): δ[] =.05 (d, J = 6.5 z, 3, - C 3 ),. (s, 9, CC(C 3 ) 3 ), (m,, 2-),.5 (s, 3, -C 3 ), (m, 8, 2 -C 3, 2 3-, 5-, 2 6-), (m,, 2-), (m,, -), (m, 2, 5-, 8a-), 2.92 (ddd, J = 2.5,., 6.6 z,, -), 3.3 (dd, J = 2.2, 2.3 z,, 7-),.78 (s,, -),.93 (s,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 9.7 (-C 3 ), 22.3 (2 -C 3 ), 25.7 (C-6), 27. (CC(C 3 ) 3 ), 27. (-C 3 ), 30.0 (C-3), 33.9 (C-5), 35.5 (C-2), 39.3 (C- ), 39.6 (CC(C 3 ) 3 ), 50. (C-), 55.7 (C-7), 6.5 (C-8a), 85.5 (C-),.9 (C- ),.2 (C-2 ), 8 2' 5 For the preparation of Burgess reagent, see: Burgess, E.M., Penton,.R., Taylor, E.A. J. rg. Chem. 973, 38, S6

7 77.8 (C= ester), 20.9 (C= ketone); RMS (ESI): [M+Na] + calcd for C Na , found Piv K 2 C 3 Me, reflux (00%) Piv ' + Piv epi-2 (R,R,R,8aR)-,-Dimethyl-8-oxo-7-(propan-2-ylidene)decahydroazulen--yl pivalate (2). K 2 C 3 (8 mg, 0.3 mmol) was added to a stirred solution of ketone 20 ( mg, 0.0 mmol) in methanol (2 ml). The resulting mixture was stirred at 70 C for h, quenched with water (0 ml) and extracted with diethyl ether (3 20 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 5:) to give enone 2 (7 mg, 50%) as a colorless oil and enone epi-2 (7 mg, 50%), which was introduced again in this step without further purification. 2: R f = 0.33 (petroleum ether/etac, 9:); [α] 20 D = 99.2 (c 0.39, C 2 Cl 2 ); NMR (00 Mz, CDCl 3 ): δ[] = 0.86 (d, J = 6.9 z, 3, -C 3 ),.6 (s, 9, CC(C 3 ) 3 ),.0.5 (m,, 2- ),.3 (s, 3, -C 3 ), (m, 2, 2-, 3-),.7 (s, 3, 2 -C 3 ),.83 (s, 3, 2 -C 3 ), (m, 2, 3-, 6-), 2.03 (ddd, J = 3.9, 8.8,.6 z,, 5-), 2. (ddd, J = 3.6,.2,.9 z,, 5-), (m,, 6-), 2.5 (dd, J =.9, 6.6 z,, 8a-), (m,, -), 2.93 (ddd, J =.2,.2, 5.8 z,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 5.9 (- C 3 ),8. (-C 3 ), 20.8 (2 -C 3 ), 2.9 (2 -C 3 ), 23.9 (C-6), 2.6 (C-3), 27.2 (CC(C 3 ) 3 ), 32.6 (C-2), 36.7 (C-5), 37. (C-), 39.5 (CC(C 3 ) 3 ),.6 (C-), 56.5 (C-8a), 86.5 (C-), 36.8 (C-2 ), 37.9 (C-7), 77.6 (C= ester), (C= ketone); RMS (ESI): [M+Na] + calcd for C Na , found epi-2 6 : R f = 0.5 (petroleum ether/etac, 9:); NMR (00 Mz, CDCl 3 ): δ[] =.05 (d, J = 6.6 z, 3, -C 3 ),.3 (s, 9, CC(C 3 ) 3 ), (m, 9),.3 (s, 3, -C 3 ),.7 (s, 3, 2 -C 3 ),.73 (s, 3, 2 -C 3 ), 2.56 (dd, J = 0.0, 7.0 z,, 8a-), 2.9 (ddd, J = 2.0, 0., 6.9 z,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 20.3, 20.8, 22.3, 2., 25.3, 27., 28., 33.7, 3., 36.9, (C-), 6. (C-8a), 85.6 (C-), 32.6 (C-2 ), 36. (C-7), 77.6 (C= ester), 20.0 (C= ketone); RMS (ESI): [M+Na] + calcd for C Na , found Piv LiAl TF, 0 C + 8 2' 2 22 (69%) epi-22 (22%) (R,R,R,8R,8aR)-,-Dimethyl-7-(propan-2-ylidene)decahydroazulene-,8-diol (22). A solution of ketone 2 (20 mg, mmol) in TF ( ml) was added dropwise to a stirred suspension of LiAl (30 mg, mmol) in TF ( ml) at 0 C. The resulting mixture was allowed to warm to ambient temperature during 2 h and then quenched by careful addition of 20% Na (0.5 ml) and water (0 ml). Stirring was continued for 5 min, before the mixture was 6 The purity of ester epi-2 was not high enough to allow for complete assignment of signals. owever, signals of 8a-, -C 3 and - were clearly observed, that allowed us to define the stereochemistry at the ring fusion. S7

8 extracted with diethyl ether (3 5 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 3:) to give diol 22 (25 mg, 69%) and diol epi-22 (8 mg, 22%) as white crystals. epi-22: R f = 0.5 (petroleum ether/etac, 2:3). 22: R f = 0.8 (petroleum ether/etac, 2:3); [α] 20 D = 29. (c 0.35, Me); NMR (00 Mz, CDCl 3 ): δ[] =.09 (d, J = 7.3 z, 3, -C 3 ),. (s, 3, -C 3 ),.2.30 (m,, 2- ),..56 (m, 3, 3-, 5-, 8a-),.65 (s, 3, 2 -C 3 ), (m, 2, 2-, 3-),.76 (s, 3, 2 -C 3 ),.93 (ddd, J =.3, 0.0,.8 z,, 5-), (m,, -), 2.2 (app dd, J = 0., 5. z,, 6-), 2.38 (app dd, J = 9., 5.7 z,, 6-), 2.66 (ddd, J = 0.0, 0.0, 8.0 z,, -),.89 (br.s,, 8-); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 6.3 (-C 3 ), 20. (2 - C 3 ), 20.7 (2 -C 3 ), 22.3 (C-6), 22.7 (-C 3 ) 25.9 (C-3), 3. (C-2), 38. (C-), 3. (C-5), 6.3 (C-), 6.5 (C-8a), 68.6 (C-8), 7.6 (C-), 26.8 (C-2 ), 36. (C-7); RMS (ESI): [M+Na] + calcd for C Na , found g(cf 3 C 2 ) 2 C 2 Cl 2 /Me, 78 C 2. NaB, Me, 78 C (95%) ' (R,R,R,7R,8R,8aR)-7-Isopropyl-,-dimethyldecahydro-,7-epoxyazulen-8-ol (23). Mercury (II) trifluoroacete (90 mg, 0.2 mmol) was added in one portion to a stirred solution of alkenediol 22 (0 mg, 0.7 mmol) in C 2 Cl 2 /Me (5 ml / 0 µl) at 78 C. The mixture was stirred overnight at the same temperature, quenched with water (20 ml) and extracted with diethyl ether (3 5 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was dissolved in Me (5 ml), cooled to 78 C and NaB (20 mg, 3.6 mmol) was added in one portion. The resulting mixture was allowed to warm to ambient temperature within 3 h, quenched with water (20 ml) and extracted with ethyl acetate (3 5 ml). The combined organic layers were washed with saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 5:) to give epoxyazulene 23 (38 mg, 95%) as white crystals. R f = 0.66 (petroleum ether/etac, :); [α] 20 D = 36.7 (c 0.55, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.83 (d, J = 6.8 z, 3, 2 -C 3 ), 0.89 (d, J = 6.8 z, 3, 2 -C 3 ), (m,, 3-),.00 (d, J = 7.3 z, 3, -C 3 ),.3 (dddd, J = 3.2, 8.3, 8.3, 2.8 z,, 2-),.25 (s, 3, -C 3 ),.2.36 (m, 2, 5-, 6-),.2 (ddd, J = 3.5, 7.2, 2.8 z,, 8a-), (m,, 3-), (m,, -, 5-, 6-, 8-),.93 (dddd, J = 3., 0.8, 8.2, 2.8 z,, 2-), 2.23 (app ddd, J = 5.0, 7., 2.6 z,, -), 2.3 (app. sept, J = 6.8 z,, 2 -), 3.80 (br.s,, 8-); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 5.9 (2 -C 3 ), 7.8 (2 -C 3 ), 9.8 (-C 3 ), 2.5 (C-3), 2.6 (-C 3 ), 27.6 (C-6), 28.2 (C-9), 30. (C-5), 32.5 (C-2), 33.8 (C-),.3 (C-),.5 (C-8a), 70.5 (C-8), 8.0 (C-), 88.9 (C-7); RMS (ESI): [M+Na] + calcd for C Na , found ' DMP, C 2 Cl 2 (89%) 8 2' 23 2 S8

9 (R,R,R,7R,8aR)-7-Isopropyl-,-dimethyloctahydro-,7-epoxyazulen-8(2)-one (2). Dess-Martin periodinane 7 (9.8 mg, 0.07 mmol) was added to a stirred solution of alcohol 23 (0.0 mg, 0.02 mmol) in C 2 Cl 2 (2 ml) at 0 C. The resulting mixture was stirred for 2 h at room temperature and then saturated Na 2 S 2 3 solution ( ml) was added, followed by addition of saturated NaC 3 solution ( ml) after 5 min. The resulting mixture was stirred for additional 5 min, the organic layer was separated and the aqueous layer extracted with C 2 Cl 2 (3 5 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac, 33:) to give ketone 2 (8.8 mg, 89%) as white crystals. R f = 0.50 (petroleum ether/etac, 9:); [α] 20 D = 9.8 (c 0.92, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.9 (d, J = 6.9 z, 6, 2 2 -C 3 ), 0.99 (d, J = 7. z, 3, -C 3 ),..2 (m, 2, 2-, 3-),.36 (s, 3, -C 3 ), (m, 3, 3-, 5-, 6-), (m, 3, 2-, 5-, 6- ), (m, 3, -, 8a-, 9-), 2.37 (app ddd, J = 3.3, 3.3, 6.5 z,, -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 6.6 (-C 3 ), 7.6 (2 -C 3 ), 8. (2 -C 3 ), 23.9 (-C 3 ), 25.5 (C-3), 29.3 (C-2`), 30. (C-), 30.5 (C-5), 3.0 (C-2), 3.5 (C-6), 52. (C-8a), 5.2 (C-), 83.8 (C-), 89.8 (C-7); (C-8); RMS (ESI): [M+Na] + calcd for C Na , found Ph Et 3 Si, TiCl C 2 Cl 2, 78 C 8 2' (72%) 8 2' cinnamic acid, -DMAP Cl 3 C 6 2 CCl, toluene (87%) 8 2' 2 25 (R,R,R,7R,8S,8aR)-7-Isopropyl-,-dimethyldecahydro-,7-epoxyazulen-8-yl cinnamate (9-deoxy-englerin) (). TiCl (5 µl, 6 µmol) was added to a stirred solution of triethylsilane (2 µl, 52 µmol) and ketone 2 (8.8 mg, 38 µmol) in C 2 Cl 2 (2 ml) at 78 C. The mixture was stirred for 30 min at this temperature, before it was quenched with saturated NaC 3 solution (2 ml). The aqueous layer was extracted with diethyl ether (3 5 ml). The combined organic layers were washed with water (0 ml), saturated NaCl solution (0 ml), dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac :) to give alcohol 25 (6. mg, 72%) as a white crystals. Triethylamine ( µl, 8 µmol) and 2,,6-trichlorobenzoyl chloride (0 µl, 67 µmol) were added successively to a stirred solution of alcohol 25 (6. mg, 27 µmol) and cinnamic acid (8.0 mg, 5 µmol) in dry toluene ( ml), followed by addition of -DMAP (0.2 mg, cat. amounts) after 0 min. The reaction mixture was stirred for 2 h, diluted with diethyl ether (0 mg), and the organic phase was washed with M Cl solution (5 ml), saturated NaC 3 solution (5 ml), saturated NaCl solution (5 ml), before it was dried over MgS, filtered and concentrated in vacuo. The residue was purified by flash chromatography (petroleum ether/etac 33:) to give 5-deoxy-englerin () (8.5 mg, 63% over 2 steps) as a colorless oil. R f = 0.6 (petroleum ether/etac, 9:); [α] 20 D = 20.6 (c 0.32, Me); NMR (00 Mz, CDCl 3 ): δ[] = 0.9 (d, J = 7. z, 3, -C 3 ), 0.95 (d, J = 6.9 z, 3, 2 -C 3 ),.00 (d, J = 6.6 z, 3, 2 -C 3 ),.00.0 m (, 3-),.8.23 (m,, 2-),.27 (s, 3, -C 3 ),.2.50 (m,, 5-), (m, 2, 6-, 8a-), (m,, -, 5-, 6-, 2 -),.93 (dddd, J = 3., 0.8, 8.2, 2.8 z,, 2-), (m, 2, -, 3-), 5.7 (d, J = 0. z,, 8-); 6.0 (d, J = 6.0 z,, -); (m, 3, 2 meta-, para-); (m, 2, 2 ortho-), 7.65 (d, J = 5.8 z,, 7 Boeckman, R. K., Jr.; Shao, P.; Mullins, J. J. rg. Synth. 2000, 77, -52. S9

10 5 -); 3 C NMR (00 Mz, CDCl 3 ): δ[] = 7.3 (-C 3 ), 7.6 (2 -C 3 ), 8. (2 -C 3 ), 2. (- C 3 ), 25.0 (C-3), 30. (C-6), 3. (C-5), 3.2 (C-2), 3.5 (C-), 33.3 (C-2 ), 7.5 (C-8a), 9.0 (C- ), 72.6 (C-8), 83.2 (C-), 86.0 (C-7), 8. (C- ), 28. (2 orto), 28.8 (2 meta), 30.2 (para), 3. (C-6 ),.7 (C-5 ), 65.8 (C= ester); RMS (ESI): [M+Na] + calcd for C , found S0

11 7.25 ' 2' f () NMR (00 Mz) spectrum of dienol 0 in CDCl C NMR (00 Mz) spectrum of dienol 0 in CDCl 3 S

12 f () NMR (00 Mz) spectrum of cyclic enone 9 in CDCl C NMR (00 Mz) spectrum of cyclic enone 9 in CDCl 3 S2

13 f () NMR (00 Mz) spectrum of epoxyketone 3 in CDCl C NMR (00 Mz) spectrum of epoxyketone 3 in CDCl 3 S3

14 f () NMR (00 Mz) spectrum of hydroxyketone in CDCl C NMR (00 Mz) spectrum of hydroxyketone in CDCl 3 S

15 f () NMR (00 Mz) spectrum of diol 5 in CDCl C NMR (00 Mz) spectrum of diol 5 in CDCl 3 S5

16 Piv f () NMR (00 Mz) spectrum of ketone 7 in CDCl C NMR (00 Mz) spectrum of ketone 7 in CDCl 3 S6

17 Piv f () NMR (00 Mz) spectrum of pivalate 8 in CDCl pivalic anhydride C NMR (00 Mz) spectrum of pivalate 8 in CDCl 3 S7

18 8 Piv 9 2' f () NMR (00 Mz) spectrum of aldol adduct 9 in CDCl C NMR (00 Mz) spectrum of aldol adduct 9 in CDCl 3 S8

19 Piv ' f () NMR (00 Mz) spectrum of enone 20 in CDCl C NMR (00 Mz) spectrum of enone 20 in CDCl 3 S9

20 Piv 2 8 2' f () NMR (00 Mz) spectrum of enone 2 in CDCl C NMR (00 Mz) spectrum of enone 2 in CDCl 3 S20

21 Piv epi f () NMR (00 Mz) spectrum of enone epi-2 in CDCl C NMR (00 Mz) spectrum of enone epi-2 in CDCl 3 S2

22 f () NMR (00 Mz) spectrum of dienol 22 in CDCl C NMR (00 Mz) spectrum of dienol 22 in CDCl 3 S22

23 8 2' f () NMR (00 Mz) spectrum of azulene 23 in CDCl C NMR (00 Mz) spectrum of azulene 23 in CDCl 3 S23

24 8 2' f () NMR (00 Mz) spectrum of ketone 2 in CDCl C NMR (00 Mz) spectrum of ketone 2 in CDCl 3 S2

25 8 2' f () NMR (00 Mz) spectrum of azulene 25 in CDCl 3 S25

26 7.25 Ph 8 2' f () NMR (00 Mz) spectrum of ( )-9-deoxy-englerin () in CDCl C NMR (00 Mz) spectrum of ( )-9-deoxy-englerin () in CDCl 3 S26