Reference of 2051-99-2, As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 2051-99-2 name is 1-Bromo-4-isobutylbenzene, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below.
General procedure: To a 50-mL two-neck round-bottom flask equipped with a cannula were added magnesium turnings (608 mg, 25 mmol), and the flask was heated at 80 C in vacuo for 1 h. A solution of the 4-isobutylphenyl bromide (426 mg, 2.0 mmol) in THF (5 mL) was added dropwise over 3 min under argon. The mixture was heated at 50 C until the reaction was initiated. Additional 4-isobutylphenyl bromide (1.71 g, 8.0 mmol) in THF (11.6 mL) was then added slowly via cannula over 15 min. The reaction mixture was heated at reflux for 3 h, after which a solution of 4-isobutylphenyl magnesium bromide 5 was obtained. To a separate 50-mL Schlenk tube was added anhydrous CoBr2 (21.9mg, 0.10mmol), and the tube was heated at 50C in vacuo for 2h. After cooling to room temperature, the cyclopropane-based bisoxazoline ligand 2 (0.12mmol) in THF (3mL) was added under argon. The resulting mixture was stirred for 1h at the same temperature, with 2-bromopropanoate 6 (1mmol) being added via syringe. The mixture solution was cooled to -80C, and the prepared Grignard reagent 5 (2.8mL, 0.5M in THF, 1.4mmol) was then added over 1h via syringe. The reaction mixture was stirred for another 6h at -80C and then quenched with saturated NH4Cl solution (5mL). The aqueous phase was extracted with diethyl ether (4¡Á10mL). The combined organic phases were dried over anhydrous Na2SO4, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (n-hexane/ethyl acetate 100:1). 4.4.1 (S)-Ethyl 2-(4-isobutylphenyl)propanoate 7a Colorless oil, 89% yield, 88:12 er. The enantiomeric ratio was determined by HPLC with a Daicel Chiralcel OJ-H column (0.5% 2-propanol in n-hexane, 0.5 mL/min, 220 nm, major tr = 12.80 min (S), minor tr = 14.45 min (R)). [alpha]D20 = +33.9 (c 1.1, CHCl3). 1H NMR (300 MHz, CDCl3) delta: 7.21 (d, J = 8.1 Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 4.18-4.06 (m, 2H), 3.68 (q, J = 7.1 Hz, 1H), 2.45 (d, J = 7.2 Hz, 2H), 1.89-1.80 (m, 1H), 1.48 (d, J = 7.2 Hz, 3H), 1.21 (t, J = 7.1 Hz, 3H), 0.90 (d, J = 6.6 Hz, 6H). 13C NMR (75 MHz, CDCl3) delta: 174.7, 140.4, 137.9, 129.2, 127.1, 60.6, 45.2, 45.0, 30.1, 22.4, 18.6, 14.1. HRMS (APCI-TOF): calcd for C15H23O2 [M+H]+ 235.1698, found 235.1707.
At the same time, in my other blogs, there are other synthetic methods of this type of compound, 1-Bromo-4-isobutylbenzene, and friends who are interested can also refer to it.
Reference:
Article; Liu, Feipeng; Bian, Qinghua; Mao, Jianyou; Gao, Zidong; Liu, Dan; Liu, Shikuo; Wang, Xueyang; Wang, Yu; Wang, Min; Zhong, Jiangchun; Tetrahedron Asymmetry; vol. 27; 14-15; (2016); p. 663 – 669;,
Bromide – Wikipedia,
bromide – Wiktionary