Hexane → 2-[1-[(1,1-Diethoxyethyl(ethoxy)phosphoryl)methyl]-2-nitro-ethyl]-1-methyl-4-nitro-benzene

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Reaction Steps

Adapting literature known protocols (U.S. Pat. No. 8,344,028; and Baylis, Tetrahedron Lett., 1995, 36(51), 9385-9388), 2-[1-[(1,1-diethoxyethyl(ethoxy)phosphoryl)-methyl]-2-nitro-ethyl]-1-methyl-4-nitro-benzene (19b) is prepared from 1-methyl-4-nitro-2-[(E)-2-nitrovinyl]benzene (19a) through 1,4-conjugate addition of lithiated commercial 1-[1-ethoxy-1-(ethoxy(methyl)phosphoryl)ethoxy]ethane (Baillie, et al., U.S. Pat. No. 4,339,443 (1982). To a solution of [1-ethoxy-1-(ethoxy(methyl)phosphoryl)ethoxy]ethane (2.65 mL, 2.69 g, 12.0 mmol) in anhydrous tetrahydrofuran (THF) (15 mL) and under a nitrogen atmosphere and at a temperature of about −78° C. (dry ice/acetone bath) is dropwise added a solution of n-butyllithium (nBuLi) in hexane (12.0 mL, 12.0 mmol). After about 30 min, the solution of the lithiated compound is added via a cannula within about 5 minutes to a cooled solution (−78° C.; dry ice/acetone bath, nitrogen atmosphere) of (19a) (2.08 g, 10.0 mmol) in anhydrous tetrahydrofuran (THF) (15 mL). The reaction is stirred at this temperature for about 30 minutes followed by gradual warming to about 0° C. (ice/water bath). Stirring is continued at this temperature for another 30 minutes. Aqueous work-up and purification by silica gel column chromatography using ethyl acetate (EtOAc) and hexanes mixtures afford the title compound (19b).

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