Synthesis of Polycyclic Benzofused Nitrogen Heterocycles via a Tandem Benzannulation/Ring-Closing Metathesis Strategy. Application in a Formal Synthesis of (+)-
A two-stage “tandem strategy” for the synthesis of benzofused nitrogen heterocycles is described that is particularly useful for the construction of systems with a high level of substitution on the benzenoid ring. The first stage in the strategy involves a benzannulation based on the reaction of cy...
| Main Authors: | , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Chemical Society
2012
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| Online Access: | http://hdl.handle.net/1721.1/69574 https://orcid.org/0000-0002-9812-206X |
| Summary: | A two-stage “tandem strategy” for the synthesis of benzofused nitrogen heterocycles is described that is particularly useful for the construction of systems with a high level of substitution on the benzenoid ring. The first stage in the strategy involves a
benzannulation based on the reaction of cyclobutenones with ynamides. This cascade process proceeds via a sequence of four pericyclic reactions and furnishes a multiply substituted aniline derivative which can bear a variety of functionalized substituents at the position ortho to the nitrogen. In the second stage of the tandem strategy, ringclosing metathesis generates the nitrogen heterocyclic ring. This two-step sequence provides efficient access to highly substituted dihydroquinolines, benzazepines, benzazocines, and related benzofused nitrogen heterocyclic systems. The application of this chemistry in a concise formal total synthesis of the anticancer agents (þ)-FR900482 and (þ)-FR66979 is described. |
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