Abstract
The first carbocupration and copper-catalyzed carbomagnesiation reactions on diversely substituted ynamides is described here. This study shows that the linear regioisomer can be quantitatively obtained in the carbometallation reaction of N-substituted alkynes.
Key words
carbocupration - carbomagnesiation - ynamides - regiochemistry - enamides
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22
General Procedure for the Stoichiometric Carbocupration Reaction.
2 O (10 mL) at -78 °C was added alkylmagnesium bromide (2 equiv). The reaction mixture was warmed to the indicated temperature and stirred for 30 min. Then, the reaction mixture was cooled to -78 °C and alkynyl amide 1 (1 equiv) in dry Et2 O was added dropwise. The reaction solution was warmed to the indicated temperature and stirred for additional 90 min. After 90 min, the reaction was quenched by a 1:2 mixture of sat. soln of NH4 Cl and NH4 OH (30%) and warmed to r.t. The phases were separated and the aqueous phases were extracted three times with Et2 O. The combined organic layers were washed with 1:2 mixture of sat. solution of NH4 Cl and NH4 OH (30%) and dried over anhyd MgSO4 .
23
General Procedure for Copper-Catalyzed Carbomagnesiation Reaction.
To a solution of alkynyl amide (1 equiv) in dry Et2 O (10 mL), copper salt (0.1 equiv) was added at r.t. The reaction mixture was cooled to -30 °C and alkylmagnesium bromide was added. Then, reaction mixture was warmed to r.t. and stirred for 90 min. After 90 min, the reaction was quenched by a 1:2 mixture of sat. soln of NH4 Cl and NH4 OH (30%) and warmed to r.t. The phases were separated and the aqueous phases were extracted three times with Et2 O. The combined organic layers were washed with 1:2 mixture of sat. soln of NH4 Cl and NH4 OH (30%) and dried over anhyd MgSO4 .
