Acylation of α-( N-carbamoyl)alkylcuprates and alkyl- or aryl(halo)cuprates

• Published in: Tetrahedron Vol. 59; no. 7; pp. 1083 - 1094
• Main Authors: Dieter, R.Karl, Sharma, Ram R., Yu, Huayun, Gore, Vinayak K.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 10.02.2003; Elsevier
• Subjects: acylation; aryl cuprates; Chemistry; Chemistry, Organic; deprotonation; Physical Sciences; Science & Technology; α-( N-carbamoyl)alkylcuprates; aryl cuprates; α-( N-carbamoyl)alkylcuprates; acylation; deprotonation; alpha-(N-carbamoyl)alkylcuprates; ASYMMETRIC-SYNTHESIS; ALCOHOL DERIVATIVES; COPPER; AMINOKETONES; CARBOXYLIC-ACID CHLORIDES; ANION SYNTHONS; ALPHA-AMINO KETONES; ACYL CHLORIDES; GRIGNARD-REAGENTS; CONJUGATE ADDITION
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/S0040-4020(02)01526-0

α-( N-Carbamoyl)alkylcuprates [R 2CuLi·LiX or RCuXLi (X=CN, Cl)] when prepared from THF soluble CuX·2LiCl (X=Cl, CN) undergo a reliable and generally high yield reaction with aroyl, alkanoyl, and alkenoyl chlorides to provide a rapid and efficient synthesis of α-carbamoyl ketones. Cuprates prepared from acyclic, cyclic, and a functionalized carbamate can be utilized. Although yields are a function of cuprate reagent and substrate structure, nearly quantitative yields can be obtained with reagents generated from 2RLi+CuCN·2LiCl. The use of reagents generated from CuCl·2LiCl are more efficient in the α-( N-carbamoyl)alkyl ligand, although yields are slightly lower. Acylation of alkyl(chloro)cuprates generated from one equivalent of CuCl·2LiCl and organolithium or Grignard reagents provides an efficient and high yield procedure for ketone synthesis. α-( N-Carbamoyl)alkylcuprates prepared from THF soluble CuX·2LiCl (X=CN, Cl) give good to excellent yields of protected α-amino ketones upon reactions with acid chlorides.