Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
The fused 6/7/5/6/6/6-hexacyclic ring system of puberuline C was assembled in 18 steps from 2-(ethoxycarbonyl)cyclohexanone. After the azabicyclo[3.3.1]nonane derivative was sequentially coupled with propargyl magnesium bromide, 2-iodo cyclopentenone and allyl bromide, the pentacycle was constructed...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Royal Society of Chemistry
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014077/ https://www.ncbi.nlm.nih.gov/pubmed/30155084 http://dx.doi.org/10.1039/c6sc00671j |
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author | Hagiwara, Koichi Tabuchi, Toshiki Urabe, Daisuke Inoue, Masayuki |
author_facet | Hagiwara, Koichi Tabuchi, Toshiki Urabe, Daisuke Inoue, Masayuki |
author_sort | Hagiwara, Koichi |
collection | PubMed |
description | The fused 6/7/5/6/6/6-hexacyclic ring system of puberuline C was assembled in 18 steps from 2-(ethoxycarbonyl)cyclohexanone. After the azabicyclo[3.3.1]nonane derivative was sequentially coupled with propargyl magnesium bromide, 2-iodo cyclopentenone and allyl bromide, the pentacycle was constructed in a single step via a radical-based cyclization/translocation/cyclization process. The C11-bridgehead radical generated via C–Br homolysis participated in a 7-endo cyclization, and the 1,5-hydrogen translocation of the resultant radical was followed by transannular 6-exo cyclization to simultaneously realize the construction of the two rings and the introduction of the five contiguous stereocenters. The last 6-exo cyclization was induced by the Mukaiyama aldol reaction, and the C16–ketone was stereoselectively reduced by the action of SmI(2)/t-BuOH, leading for the first time to the synthesis of the entire hexacycle of puberuline C. |
format | Online Article Text |
id | pubmed-6014077 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-60140772018-08-28 Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process Hagiwara, Koichi Tabuchi, Toshiki Urabe, Daisuke Inoue, Masayuki Chem Sci Chemistry The fused 6/7/5/6/6/6-hexacyclic ring system of puberuline C was assembled in 18 steps from 2-(ethoxycarbonyl)cyclohexanone. After the azabicyclo[3.3.1]nonane derivative was sequentially coupled with propargyl magnesium bromide, 2-iodo cyclopentenone and allyl bromide, the pentacycle was constructed in a single step via a radical-based cyclization/translocation/cyclization process. The C11-bridgehead radical generated via C–Br homolysis participated in a 7-endo cyclization, and the 1,5-hydrogen translocation of the resultant radical was followed by transannular 6-exo cyclization to simultaneously realize the construction of the two rings and the introduction of the five contiguous stereocenters. The last 6-exo cyclization was induced by the Mukaiyama aldol reaction, and the C16–ketone was stereoselectively reduced by the action of SmI(2)/t-BuOH, leading for the first time to the synthesis of the entire hexacycle of puberuline C. Royal Society of Chemistry 2016-07-01 2016-03-18 /pmc/articles/PMC6014077/ /pubmed/30155084 http://dx.doi.org/10.1039/c6sc00671j Text en This journal is © The Royal Society of Chemistry 2016 http://creativecommons.org/licenses/by-nc/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported Licence (CC BY-NC 3.0) |
spellingShingle | Chemistry Hagiwara, Koichi Tabuchi, Toshiki Urabe, Daisuke Inoue, Masayuki Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process |
title | Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
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title_full | Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
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title_fullStr | Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
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title_full_unstemmed | Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
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title_short | Expeditious synthesis of the fused hexacycle of puberuline C via a radical-based cyclization/translocation/cyclization process
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title_sort | expeditious synthesis of the fused hexacycle of puberuline c via a radical-based cyclization/translocation/cyclization process |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014077/ https://www.ncbi.nlm.nih.gov/pubmed/30155084 http://dx.doi.org/10.1039/c6sc00671j |
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