2-Methylenecyclopropanecarboxylic acid ethyl ester

[18941-94-1] C7H10O2 (MW 126.15) InChI = 1S/C7H10O2/c1-3-9-7(8)6-4-5(6)2/h6H,2-4H2,1H3 InChIKey = SPCOBAXZQGNBHE-UHFFFAOYSA-N (building block used for the preparation of a variety of hydroxymethylmethylenecyclopropyl,1 fluoromethylenecyclopropyl,2 methylene-2-ethynylcyclopropyl,3 and spiro[2.2]pentyl4 nucleoside analogs; has also been used as a readily available starting material for the synthesis of (±)-hypoglycin A5 and (R)-(−) and (S)-(+)-synadenol6) Alternate Name: ethyl methylenecyclopropanecarboxylate, 2-ethoxycarbonyl-1-methylenecyclopropane. Physical Data: bp 152–154 °C/760 mmHg.5 Solubility: soluble in most organic solvents. Form Supplied in: colorless oil; the title compound is not available through commercial sources. Preparative Methods: 2-methylenecyclopropanecarboxylic acid ethyl ester 1 is prepared by the reaction of 2-bromopropene and ethyl diazoacetate by a rhodium acetate catalyzed cylopropanation followed by elimination with sodium hydride.7, 8 Less efficiently, a copper-bronze catalyst may be used in the former reaction.5 This can also be synthesized by a Michael addition of 1-chloro-1-nitroethane to ethyl acrylate after subsequent cyclization and elimination with excess sodium hydride.9 A mixture of zinc–copper couple, iodine, methylene iodide, and ethyl buta-2,3-dienoate in refluxing diethyl ether has proven efficient to yield title compound 1.10 Purification: distilled under reduced pressure. Handling, Storage, and Precautions: normal laboratory precautions should be taken.