Ethyl Acrylate → tert-butyl (3RS,4RS)-4-[4-(2-ethoxycarbonyl-vinyl)-phenyl]-3-hydroxy-piperidine-1-carboxylate

Beteiligte Stoffe

Reaktionsschritte

A Schlenk tube was charged under argon with 25.6 mg (0.114 mmol) of Pd(OAc)2, 69.6 mg (0.Z29 mmol) of tri(o-tolyl)phosphine and 20 ml of DMF (distilled under argon) and the reaction mixture was stirred at room temperature for 1 5 minutes. A 200 ml sulphonation flask was charged under argon and while stirring with 8.15 g (22.9 mmol) of tert-butyl (3RS,4RS)-4-(4-bromo-phenyl)-3-hydroxy-piperidine-1-carboxylate [Example 25 (c)], 100 ml of DMF, 3.73 ml (34.3 mmol) of ethyl acrylate, 2.25 g (27.5 mmol) of sodium acetate and the yellow catalyst solution. The reaction mixture was stirred at 120° C. for 6 hours. In order to complete the reaction, a solution of 5.1 mg Pd(OAc)2 and 14.3 mg of tri(o-tolyl)phosphine in 5 ml of DMF was added after 5 hours. The dark reaction mixture was evaporated on a rotary evaporator. The grey solid residue was taken up in ether and the turbid solution was washed three times with water, dried over sodium sulphate and evaporated under reduced pressure. The yellow solid residue was chromatographed on 250 g of silica gel using a 2:1 mixture of hexane and ethyl acetate as the eluent. After crystallization from ethyl acetate there were obtained 6.66 g (77% of theory) of tert-butyl (3RS,4RS)-4-[4-(2-ethoxycarbonyl-vinyl)-phenyl]-3-hydroxy-piperidine-1-carboxylate as colourless crystals; MS: 376 (M+H)+.

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