8-oxabicyclo[3.2.1]oct-6-en-3-one

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a stirred solution of 1,3-dipropyl-7-pyrrolidin-1-ylmethyl-3,7-dihydro-purine-2,6-dione (Example 48) (522 mg, 1.63 mmol) in THF (50 ml) at −78° C. was added n-BuLi (1.55 M in hexanes, 1.2 eq, 1.3 ml). The color of the resulting yellow mixture deepened to orange-red and was stirred at this temperature for 0.5 h. A solution of 8-oxa-bicyclo[3.2.1]oct-6-en-3-one (1.1 eq, 222 mg, 1.79 mmol) in THF (4 ml) was added via syringe over a period of 20 minutes. The mixture was held at −78° C. for 2 h and allowed to reach ambient temperature overnight (12 h). The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) and the aqueous phase was extracted with EtOAc (20 ml). The combined organic extracts were washed with saturated aqeuous NaCl (20 ml), dried (MgSO4), filtered and concentrated in vacuo. The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that solidified upon standing (50 mg, 8%). The mixture was held at −78° C. for 2 h to reach ambient temperature overnight (12 h) The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) the aqueous phase was extracted with EtOAc (20 ml) The combined organic extracts were washed with saturated aqeuous NaCl (20 ml) dried (MgSO4) filtered concentrated in vacuo The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3] cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999, 64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsatured ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3] cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999, 64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsatured ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3]cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999,64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsaturated ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3]cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999,64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsaturated ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: To a stirred solution of 1,3-dipropyl-7-pyrrolidin-1-ylmethyl-3,7-dihydro-purine-2,6-dione (Example 48) (522 mg, 1.63 mmol) in THF (50 ml) at −78° C. was added n-BuLi (1.55 M in hexanes, 1.2 eq, 1.3 ml). The color of the resulting yellow mixture deepened to orange-red and was stirred at this temperature for 0.5 h. A solution of 8-oxa-bicyclo[3.2.1]oct-6-en-3-one (1.1 eq, 222 mg, 1.79 mmol) in THF (4 ml) was added via syringe over a period of 20 minutes. The mixture was held at −78° C. for 2 h and allowed to reach ambient temperature overnight (12 h). The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) and the aqueous phase was extracted with EtOAc (20 ml). The combined organic extracts were washed with saturated aqeuous NaCl (20 ml), dried (MgSO4), filtered and concentrated in vacuo. The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that solidified upon standing (50 mg, 8%). The mixture was held at −78° C. for 2 h to reach ambient temperature overnight (12 h) The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) the aqueous phase was extracted with EtOAc (20 ml) The combined organic extracts were washed with saturated aqeuous NaCl (20 ml) dried (MgSO4) filtered concentrated in vacuo The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3] cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999, 64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsatured ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: 8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3]cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999,64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsaturated ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).

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

Procedure: To a stirred solution of 1,3-dipropyl-7-pyrrolidin-1-ylmethyl-3,7-dihydro-purine-2,6-dione (Example 48) (522 mg, 1.63 mmol) in THF (50 ml) at −78° C. was added n-BuLi (1.55 M in hexanes, 1.2 eq, 1.3 ml). The color of the resulting yellow mixture deepened to orange-red and was stirred at this temperature for 0.5 h. A solution of 8-oxa-bicyclo[3.2.1]oct-6-en-3-one (1.1 eq, 222 mg, 1.79 mmol) in THF (4 ml) was added via syringe over a period of 20 minutes. The mixture was held at −78° C. for 2 h and allowed to reach ambient temperature overnight (12 h). The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) and the aqueous phase was extracted with EtOAc (20 ml). The combined organic extracts were washed with saturated aqeuous NaCl (20 ml), dried (MgSO4), filtered and concentrated in vacuo. The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that solidified upon standing (50 mg, 8%). The mixture was held at −78° C. for 2 h to reach ambient temperature overnight (12 h) The reaction mixture was partitioned between saturated aqeuous NH4Cl (20 ml) and EtOAc (20 ml) the aqueous phase was extracted with EtOAc (20 ml) The combined organic extracts were washed with saturated aqeuous NaCl (20 ml) dried (MgSO4) filtered concentrated in vacuo The resulting orange oil was purified by chromatography on silica using 5% MeOH in CH2Cl2 as eluent to give a clear oil that