Diethyl Ether → Ethyl 9-(2,6,6-trimethylcyclohex-1-en-1-yl)nonanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To freshly prepared ethyl 9-(bromozincio)nonanoate (37.7 mmol) in dimethylacetamide under nitrogen in a reaction tube was added 2,6,6-trimethylcyclohex-1-en-1-yl trifluoromethanesulfonate (10.8 g, 39.6 mmol) followed by tetrakis(triphenylphosphine)palladium(0) (872 mg, 0.754 mmol). The tube was sealed and the mixture was stirred at 95° C. for 2 h. The reaction mixture was allowed to cool and was then poured into diethyl ether (100 mL). The upper layer was decanted and the lower layer was washed twice with diethyl ether (2×25 mL). The combined ether layers were washed with sat NH4Cl and brine, dried (MgSO4) and concentrated to give crude material (˜12 g). The material was purified by flash chromatography (silica, 0 to 1.5% EtOAc in hexane). The obtained oil was stirred under vacuum for 8 h in order to remove most of the side-product, ethyl nonanoate, and was then purified by a second flash chromatography (silica, 0 to 15% toluene in hexane). The fractions were analyzed by LCMS and GCMS. The purest fractions were collected and concentrated at a temperature below 25° C. to give ethyl 9-(2,6,6-trimethylcyclohex-1-en-1-yl)nonanoate as a colorless oil (6.16 g, 53% yield over two steps). LCMS ESI+m/z 309 [M+H]+; GCMS m/z 308 [M]+.

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