dimethyl 2-diazopropanedioate

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

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

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

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

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: To stirred solution of 79 g of 6-methoxy-2H-[1]benzopyran (J. Org. Chem. 1973, 38, 3832) and 17.6 g of cuprous iodide-trimethyl phosphite (Synthesis 1971, 658) in 400 ml toluene, is added at 103° 125 g dimethyl diazomalonate (Synthesis 1971, 658) over a period of 30 min. After stirring 1.5 h, the reaction mixture is cooled, filtered through Celite, concentrated under reduced pressure and flash chromatographed with ethyl acetate/hexane (3:7) to give cis-(±)-dimethyl 1,1a,2,7b-tetrahydro-6-methoxybenzo[b]cyclopropa[d]pyran-1,1-dicarboxylate. the reaction mixture is cooled filtered through Celite concentrated under reduced pressure and flash chromatographed with ethyl acetate/hexane (3:7)

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of t-butyldiphenyl-(3-phenyl-3-butenyloxy)-silane (3.0 g, 7.0 mmol) and dimethyl diazomalonate (1.1 g, 7.0 mmol), which was synthesized by the method described in Synth. Commun. (1987, 17, 1709-1716), was added rhodium (II) acetate dimmer (62 mg, 0.14 mmol) under argon atmosphere, and the mixture was heated at 100° C. for 10 min. After cooling to room temperature, the mixture was diluted with chloroform (4 mL), separated and purified by silica gel chromatography (hexane:ethyl acetate=100:0 to 4:1) to give the title compound (2.5 g, yield 70%) as a colorless oil. was synthesized by the method After cooling to room temperature separated purified by silica gel chromatography (hexane:ethyl acetate=100:0 to 4:1)

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a mixture of t-butyldiphenyl-(3-phenyl-3-butenyloxy)-silane (3.0 g, 7.0 mmol) and dimethyl diazomalonate (1.1 g, 7.0 mmol), which was synthesized by the method described in Synth. Commun. (1987, 17, 1709-1716), was added rhodium (II) acetate dimmer (62 mg, 0.14 mmol) under argon atmosphere, and the mixture was heated at 100° C. for 10 min. After cooling to room temperature, the mixture was diluted with chloroform (4 mL), separated and purified by silica gel chromatography (hexane:ethyl acetate=100:0 to 4:1) to give the title compound (2.5 g, yield 70%) as a colorless oil. was synthesized by the method After cooling to room temperature separated purified by silica gel chromatography (hexane:ethyl acetate=100:0 to 4:1)

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

Procedure: 4-Octyne and dimethyl diazomalonate were reacted in the presence of cupric acetylacetonate in a manner similar to that described in Example XCVII Part A to give dimethyl 2,3-di-n-propyl-2-cyclopropene-1,1-dicarboxylate which was saponified to give mono-methyl 2,3-di-n-propyl-2-cyclopropene-1,1-dicarboxylate and worked up by the general procedure of Example XCVII Part B. Reaction of the latter mono-methyl ester in sequence with ethyl chloroformate and 4-bromo-2-methylaniline, in the presence of potassium carbonate and 18-crown-6, in a manner similar to that described in Example XCIX Part B to give methyl 1-(4-bromo-2-methylphenyl-aminocarbonyl)-2,3-di-n-propyl-2-cyclopropenecarboxylate having a melting point of 52° C.-54° C.

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

Procedure: A nitrogen-degassed solution of 37.5 grams (0.69 mole) of 2-butyne and 20.0 grams (0.13 mole) of dimethyl diazomalonate in approximately 325 grams of hexafluorobenzene was photolyzed for approximately 100 hours, at 0° C.-5° C., employing a 100-watt Hanovia mercury lamp in a manner similar to that described in Example XCVI Part A. Similar workup of the reaction mixture afforded 10.8 grams (0.06 mole) of dimethyl 2,3-dimethyl-2-cyclopropene-1,1-dicarboxylate. NMR analysis of the product indicated the following:

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

Procedure: A nitrogen-degassed solution of 37.5 grams (0.69 mole) of 2-butyne and 20.0 grams (0.13 mole) of dimethyl diazomalonate in approximately 325 grams of hexafluorobenzene was photolyzed for approximately 100 hours, at 0° C.-5° C., employing a 100-watt Hanovia mercury lamp in a manner similar to that described in Example XCVI Part A. Similar workup of the reaction mixture afforded 10.8 grams (0.06 mole) of dimethyl 2,3-dimethyl-2-cyclopropene-1,1-dicarboxylate. NMR analysis of the product indicated the following: