Iodine → HCID 57831240, compound

Participants

Reaction Conditions

Reaction Steps

A little iodine was added to a mixture of 5.6 g (3 eq) magnesium and 20 ml dry diethyl ether, followed over a period of 10 min by 5 g 2-bromothiophene, and the mixture was stirred for a further 10 min. Once the reaction had started, 33.5 g (2.6 eq) 2-bromothiophene dissolved in 80 ml diethyl ether were added dropwise and the mixture was stirred for a period of 2 h at room temperature. The Grignard reagent prepared in the preceding step was added dropwise to a solution of 20 g (1 eq) tert-butyloxycarbonyl-4-cyano-4-(dimethylamino)-piperidine dissolved in 200 ml THF and stirred overnight at room temperature. The reaction course was monitored by thin-layer chromatography (50% EtOAc/hexane). Once the conversion was complete, the reaction solution was cooled to 0° C., mixed with saturated NH4Cl solution, extracted with ethyl acetate (3×100 ml) and the combined organic phases were dried with Na2SO4. Following removal of the solvent under reduced pressure, the residue was purified by column chromatography (Alox neutral; 30% EtOAc/hexane). 6.1 g (25%) of product were obtained in the form of a white solid.

Provenance & Evidence