Hydrogen bond-directed stereoselective synthesis of Z-enamides via catalytic olefination reactions of primary amides

ORGN 206

Ji Min Lee, sunnylee@kaist.ac.kr1, Doo Young Jung1, Min Kim, sunnylee@kaist.ac.kr1, and Sukbok Chang, sbchang@kaist.ac.kr2. (1) Department of Chemistry, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, DaeJeon, 305-701, South Korea, (2) Department of Chemistry and School of Molecular Science (BK 21), Korea Advanced Institute of Science and Tchonolgy (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701, South Korea
Highly stereoselective preparation of a variety of Z-enamides is achieved by the reaction of primary amides and electron-withdrawing olefins using Pd(II) and Cu(I) cocalysts under oxygen atmosphere. Under the Wacker-type reaction condition, a variety of primary amides were olefinated with electron-deficient alkenes with high efficiency and excellent selectivity. The observed preferential generation of Z-enamides is attributed to the intramolecular hydrogen bonding present in the isomers whereas corresponding E-isomers do not have the interactions. This is confirmed by the computational calculations which reveal that Z-isomer is stabilized by ca 5 kcal/mol compared to E-enamides. Facile isomerization of Z-enamides to E-isomers is readily achieved with synthetically useful efficiency and selectivity, thus ways for the preparation of both Z- and E-enamides are now opened. Synthetic application of the present method is demonstrated by the facile preparation of cis-CJ-15,801 compound.
 

Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006