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Attempts to improve the overall stereoselectivity of the Ireland-Claisen rearrangement.

ABSTRACT: With focus on the steric effects present in the transition states for the [3,3]-sigmatropic rearrangement, the substrate 5 has been designed to improve the overall stereoselectivity of the Ireland-Claisen rearrangement. Experimentally, it has been found that (1) only Z-6 rearranges to 7 at 80 degrees C and (2) E-6 isomerizes to Z-6 at 80 degrees C, thereby allowing the transformation of 5 into 7 in an almost quantitative yield. To illustrate the usefulness of this approach, two additional examples are given.

SUBMITTER: Chen CL

PROVIDER: S-EPMC2659616 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

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Attempts to improve the overall stereoselectivity of the Ireland-Claisen rearrangement.

Chen Chi-Li CL Namba Kosuke K Kishi Yoshito Y

Organic letters 20090101 2

With focus on the steric effects present in the transition states for the [3,3]-sigmatropic rearrangement, the substrate 5 has been designed to improve the overall stereoselectivity of the Ireland-Claisen rearrangement. Experimentally, it has been found that (1) only Z-6 rearranges to 7 at 80 degrees C and (2) E-6 isomerizes to Z-6 at 80 degrees C, thereby allowing the transformation of 5 into 7 in an almost quantitative yield. To illustrate the usefulness of this approach, two additional exampl ...[more]

PMID: 19128191

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