Collect. Czech. Chem. Commun. 2008, 73, 1705-1718

Michael Addition Reactions to 3-(4-Chloro-4,4-difluorobut-2-enoyl)oxazolidin-2-one

Miyako Fukuda, Tomoko Kawasaki-Takasuka and Takashi Yamazaki*

Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei, 184-8588, Japan


1,4-Addition reactions to chlorodifluorinated Michael acceptor 1b containing a chiral oxazolidinone auxiliary were found to proceed smoothly either with alkyllithium or Grignard reagents in the presence of CuY (Y = I or CN) or ZnCl2. In contrast to the corresponding cuprates, R2Zn or R3ZnMgBr species (prepared from 2 or 3 equiv. of RMgX and ZnCl2, respectively) were quite effective in suppression of the unfavorable β-elimination mechanism leading to the terminally difluorinated byproduct 3.

Keywords: Michael addition; Cuprates; Organozinc reagents; Chlorodifluoromethyl.

References: 24 live references.