8a-methyl-3,4,7,8-tetrahydro-2H-naphthalene-1,6-dione

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3,4,8,8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione (2.5 g, 0.014 mole) in dry tetrahydrofuran (20 ml) was added to lithium diisopropylamide [made from dry diisopropylamine (1.95 ml 0.014 mole) and n-butyl-lithium (12.0 ml of a 1.15 M solution in hexane, 0.014 mole)] at -65° C. under nitrogen. The solution was allowed to warm to 0° C. and a solution of benzyl bromide (2.39 g, 0.014 mole) in dry tetrahydrofuran (6 ml) was added. This was stirred at room temperature overnight, poured into water and extracted with diethyl ether (100 ml). The organic phase was washed with 1 N hydrochloric acid (50 ml) and water (50 ml), then dried (Na2SO4) and evaported to give a dark oil. This was chromatographed on silica gel using diethyl ether/petroleum ether (1:1) as eluant giving the title compound which was further purified by distillation b.p. 190° C./0.01 mm. The product was isolated as a mixture of isomers. at -65° C. extracted with diethyl ether (100 ml) The organic phase was washed with 1 N hydrochloric acid (50 ml) and water (50 ml) dried (Na2SO4) to give a dark oil This was chromatographed on silica gel

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of Wieland-Miescher ketone (5.87 g, 33.0 mmol) in glacial acetic acid (40 mL) was added p-toluenesulfonic acid (2.94 g) followed by dropwise addition of 1,2-ethanedithiol over a 1 hour period. The reaction mixture was stirred at room temperature for another 4 hours, poured into 30 mL water, and stirred for 15 minutes. The white solid was filtered off, washed successively with water, diluted with NaHCO3 solution and water, and then dried to yield thioketal 239 (7.33 g, 87.3%) as a white solid. 1H NMR (CDCl3) δ 1.50-2.70 (m, 10H), 3.20-3.40 (m, 4H), 5.67 (s, 1H); 13C NMR (CDCl3) 212.92, 141.23, 128.04, 64.81, 49.43, 40.11, 39.62, 37.92, 37.57, 30.81, 30.69, 24.73, 24.57. stirred for 15 minutes The white solid was filtered off washed successively with water diluted with NaHCO3 solution and water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4, and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27. The reaction was quenched with dropwise addition of triethylamine diluted with 20 mL of benzene washed with water dried over MgSO4 concentrated under vacuum The product was triturated from hexanes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of Wieland-Miescher ketone (5.87 g, 33.0 mmol) in glacial acetic acid (40 mL) was added p-toluenesulfonic acid (2.94 g) followed by dropwise addition of 1,2-ethanedithiol over a 1 hour period. The reaction mixture was stirred at room temperature for another 4 hours, poured into 30 mL water, and stirred for 15 minutes. The white solid was filtered off, washed successively with water, diluted with NaHCO3 solution and water, and then dried to yield thioketal 239 (7.33 g, 87.3 %) as a white solid. 1H NMR (CDCl3) δ 1.50-2.70 (m, 10H), 3.20-3.40 (m, 4H), 5.67 (s, 1H); 13C NMR (CDCl3) 212.92, 141.23, 128.04, 64.81, 49.43, 40.11, 39.62, 37.92, 37.57, 30.81, 30.69, 24.73, 24.57. stirred for 15 minutes The white solid was filtered off washed successively with water diluted with NaHCO3 solution and water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of Wieland-Miescher ketone (5.87 g, 33.0 mmol) in glacial acetic acid (40 mL) was added p-toluenesulfonic acid (2.94 g) followed by dropwise addition of 1,2-ethanedithiol over a 1 hour period. The reaction mixture was stirred at room temperature for another 4 hours, poured into 30 mL water, and stirred for 15 minutes. The white solid was filtered off, washed successively with water, diluted with NaHCO3 solution and water, and then dried to yield thioketal 239 (7.33 g, 87.3 %) as a white solid. 1H NMR (CDCl3) δ 1.50-2.70 (m, 10H), 3.20-3.40 (m, 4H), 5.67 (s, 1H); 13C NMR (CDCl3) 212.92, 141.23, 128.04, 64.81, 49.43, 40.11, 39.62, 37.92, 37.57, 30.81, 30.69, 24.73, 24.57. stirred for 15 minutes The white solid was filtered off washed successively with water diluted with NaHCO3 solution and water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27. The reaction was quenched with dropwise addition of triethylamine diluted with 20 mL of benzene washed with water dried over MgSO4and concentrated under vacuum The product was triturated from hexanes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27. The reaction was quenched with dropwise addition of triethylamine diluted with 20 mL of benzene washed with water dried over MgSO4and concentrated under vacuum The product was triturated from hexanes

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of Wieland-Miescher ketone (5.87 g, 33.0 mmol) in glacial acetic acid (40 mL) was added p-toluenesulfonic acid (2.94 g) followed by dropwise addition of 1,2-ethanedithiol over a 1 hour period. The reaction mixture was stirred at room temperature for another 4 hours, poured into 30 mL water, and stirred for 15 minutes. The white solid was filtered off, washed successively with water, diluted with NaHCO3 solution and water, and then dried to yield thioketal 239 (7.33 g, 87.3%) as a white solid. 1H NMR (CDCl3) δ 1.50-2.70 (m, 10H), 3.20-3.40 (m, 4H), 5.67 (s, 1H); 13C NMR (CDCl3) 212.92, 141.23, 128.04, 64.81, 49.43, 40.11, 39.62, 37.92, 37.57, 30.81, 30.69, 24.73, 24.57. stirred for 15 minutes The white solid was filtered off washed successively with water diluted with NaHCO3 solution and water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4, and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27. The reaction was quenched with dropwise addition of triethylamine diluted with 20 mL of benzene washed with water dried over MgSO4 concentrated under vacuum The product was triturated from hexanes

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 3,4,8,8a-tetrahydro-8a-methyl-1,6(2H,7H)-naphthalenedione (2.5 g, 0.014 mole) in dry tetrahydrofuran (20 ml) was added to lithium diisopropylamide [made from dry diisopropylamine (1.95 ml 0.014 mole) and n-butyl-lithium (12.0 ml of a 1.15 M solution in hexane, 0.014 mole)] at -65° C. under nitrogen. The solution was allowed to warm to 0° C. and a solution of benzyl bromide (2.39 g, 0.014 mole) in dry tetrahydrofuran (6 ml) was added. This was stirred at room temperature overnight, poured into water and extracted with diethyl ether (100 ml). The organic phase was washed with 1 N hydrochloric acid (50 ml) and water (50 ml), then dried (Na2SO4) and evaported to give a dark oil. This was chromatographed on silica gel using diethyl ether/petroleum ether (1:1) as eluant giving the title compound which was further purified by distillation b.p. 190° C./0.01 mm. The product was isolated as a mixture of isomers. at -65° C. extracted with diethyl ether (100 ml) The organic phase was washed with 1 N hydrochloric acid (50 ml) and water (50 ml) dried (Na2SO4) to give a dark oil This was chromatographed on silica gel

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of Wieland-Miescher ketone (5.87 g, 33.0 mmol) in glacial acetic acid (40 mL) was added p-toluenesulfonic acid (2.94 g) followed by dropwise addition of 1,2-ethanedithiol over a 1 hour period. The reaction mixture was stirred at room temperature for another 4 hours, poured into 30 mL water, and stirred for 15 minutes. The white solid was filtered off, washed successively with water, diluted with NaHCO3 solution and water, and then dried to yield thioketal 239 (7.33 g, 87.3%) as a white solid. 1H NMR (CDCl3) δ 1.50-2.70 (m, 10H), 3.20-3.40 (m, 4H), 5.67 (s, 1H); 13C NMR (CDCl3) 212.92, 141.23, 128.04, 64.81, 49.43, 40.11, 39.62, 37.92, 37.57, 30.81, 30.69, 24.73, 24.57. stirred for 15 minutes The white solid was filtered off washed successively with water diluted with NaHCO3 solution and water dried

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4, and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27. The reaction was quenched with dropwise addition of triethylamine diluted with 20 mL of benzene washed with water dried over MgSO4 concentrated under vacuum The product was triturated from hexanes