These common heterocyclic compound, 2051-99-2, name is 1-Bromo-4-isobutylbenzene, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. SDS of cas: 2051-99-2
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 (4×10mL). 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). 4.4.5 (S)-Benzyl 2-(4-isobutylphenyl)propanoate 7e Colorless oil, 93% yield, 91:9 er. The enantiomeric ratio was determined by HPLC with a Daicel Chiralcel OJ-H column (8.0% 2-propanol in n-hexane, 0.5 mL/min, 220 nm, minor tr = 16.94 min (R), major tr = 21.49 min (S)). [alpha]D20 = +76.1 (c 1.1, CHCl3). 1H NMR (300 MHz, CDCl3) delta: 7.36-7.07 (m, 9H), 5.15-5.06 (m, 2H), 3.75 (q, J = 7.2 Hz, 1H), 2.45 (d, J = 7.2 Hz, 2H), 1.89-1.80 (m, 1H), 1.51 (d, J = 7.2 Hz, 3H), 0.90 (d, J = 6.6 Hz, 6H). 13C NMR (75 MHz, CDCl3) delta: 174.5, 140.5, 137.6, 136.1, 129.3, 128.4, 127.9, 127.7, 127.2, 66.2, 45.1, 45.0, 30.2, 22.3, 18.4. HRMS (APCI-TOF): calcd for C20H25O2 [M+H]+ 297.1855, found 297.1854.
The synthetic route of 1-Bromo-4-isobutylbenzene has been constantly updated, and we look forward to future research findings.
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;,
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bromide – Wiktionary