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Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement
Iridium(I) N‐heterocyclic carbene complexes of formula Ir(κ(2) O,O’‐BHetA)(IPr)(η (2)‐coe) [BHetA=bis‐heteroatomic acidato, acetylacetonate or acetate; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐carbene; coe=cyclooctene] have been prepared by treating Ir(κ(2) O,O’‐BHetA)(η (2)‐coe)(2) complexes...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8453560/ https://www.ncbi.nlm.nih.gov/pubmed/33998070 http://dx.doi.org/10.1002/chem.202101414 |
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author | Azpíroz, Ramón Greger, Ingo Oro, Luis A. Passarelli, Vincenzo Castarlenas, Ricardo Pérez‐Torrente, Jesús J. |
author_facet | Azpíroz, Ramón Greger, Ingo Oro, Luis A. Passarelli, Vincenzo Castarlenas, Ricardo Pérez‐Torrente, Jesús J. |
author_sort | Azpíroz, Ramón |
collection | PubMed |
description | Iridium(I) N‐heterocyclic carbene complexes of formula Ir(κ(2) O,O’‐BHetA)(IPr)(η (2)‐coe) [BHetA=bis‐heteroatomic acidato, acetylacetonate or acetate; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐carbene; coe=cyclooctene] have been prepared by treating Ir(κ(2) O,O’‐BHetA)(η (2)‐coe)(2) complexes with IPr. These complexes react with 2‐vinylpyridine to afford the hydrido‐iridium(III)‐alkenyl cyclometalated derivatives IrH(κ(2) O,O’‐BHetA)(κ(2) N,C‐C(7)H(6)N)(IPr) through the iridium(I) intermediate Ir(κ(2) O,O’‐BHetA)(IPr)(η (2)‐C(7)H(7)N). The cyclometalated IrH(κ(2) O,O’‐acac)(κ(2) N,C–C(7)H(6)N)(IPr) complex efficiently catalyzes the hydroalkenylation of aromatic and aliphatic terminal alkynes and enynes with 2‐vinylpyridine to afford 2‐(4R‐butadienyl)pyridines with Z,E configuration as the major reaction products (yield up to 89 %). In addition, unprecedented (Z)‐2‐butadienyl‐5R‐pyridine derivatives have been obtained as minor reaction products (yield up to 21 %) from the elusive 1Z,3gem‐butadienyl hydroalkenylation products. These compounds undergo a thermal 6π‐electrocyclization to afford bicyclic 4H‐quinolizine derivatives that, under catalytic reaction conditions, tautomerize to 6H‐quinolizine to afford the (Z)‐2‐(butadienyl)‐5R‐pyridine by a retro‐electrocyclization reaction. |
format | Online Article Text |
id | pubmed-8453560 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-84535602021-09-27 Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement Azpíroz, Ramón Greger, Ingo Oro, Luis A. Passarelli, Vincenzo Castarlenas, Ricardo Pérez‐Torrente, Jesús J. Chemistry Full Papers Iridium(I) N‐heterocyclic carbene complexes of formula Ir(κ(2) O,O’‐BHetA)(IPr)(η (2)‐coe) [BHetA=bis‐heteroatomic acidato, acetylacetonate or acetate; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐carbene; coe=cyclooctene] have been prepared by treating Ir(κ(2) O,O’‐BHetA)(η (2)‐coe)(2) complexes with IPr. These complexes react with 2‐vinylpyridine to afford the hydrido‐iridium(III)‐alkenyl cyclometalated derivatives IrH(κ(2) O,O’‐BHetA)(κ(2) N,C‐C(7)H(6)N)(IPr) through the iridium(I) intermediate Ir(κ(2) O,O’‐BHetA)(IPr)(η (2)‐C(7)H(7)N). The cyclometalated IrH(κ(2) O,O’‐acac)(κ(2) N,C–C(7)H(6)N)(IPr) complex efficiently catalyzes the hydroalkenylation of aromatic and aliphatic terminal alkynes and enynes with 2‐vinylpyridine to afford 2‐(4R‐butadienyl)pyridines with Z,E configuration as the major reaction products (yield up to 89 %). In addition, unprecedented (Z)‐2‐butadienyl‐5R‐pyridine derivatives have been obtained as minor reaction products (yield up to 21 %) from the elusive 1Z,3gem‐butadienyl hydroalkenylation products. These compounds undergo a thermal 6π‐electrocyclization to afford bicyclic 4H‐quinolizine derivatives that, under catalytic reaction conditions, tautomerize to 6H‐quinolizine to afford the (Z)‐2‐(butadienyl)‐5R‐pyridine by a retro‐electrocyclization reaction. John Wiley and Sons Inc. 2021-06-21 2021-08-16 /pmc/articles/PMC8453560/ /pubmed/33998070 http://dx.doi.org/10.1002/chem.202101414 Text en © 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
spellingShingle | Full Papers Azpíroz, Ramón Greger, Ingo Oro, Luis A. Passarelli, Vincenzo Castarlenas, Ricardo Pérez‐Torrente, Jesús J. Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title | Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title_full | Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title_fullStr | Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title_full_unstemmed | Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title_short | Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement |
title_sort | preparation of butadienylpyridines by iridium‐nhc‐catalyzed alkyne hydroalkenylation and quinolizine rearrangement |
topic | Full Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8453560/ https://www.ncbi.nlm.nih.gov/pubmed/33998070 http://dx.doi.org/10.1002/chem.202101414 |
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