| Title: |
Magnesium‐Catalyzed Tandem Dehydrogenation‐Dehydrocoupling: An Atom Economical Access to Alkynylboranes |
| Authors: |
Birepinte, Mélodie; Liautard, Virginie; Chabaud, Laurent; Pucheault, Mathieu |
| Contributors: |
Institut des Sciences Moléculaires (ISM); Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Université Sciences et Technologies - Bordeaux 1-Université Montesquieu - Bordeaux 4-Institut de Chimie du CNRS (INC) |
| Source: |
ISSN: 0947-6539. |
| Publisher Information: |
HAL CCSD; Wiley-VCH Verlag |
| Publication Year: |
2020 |
| Collection: |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
| Subject Terms: |
[CHIM.ORGA]Chemical Sciences/Organic chemistry |
| Description: |
International audience ; Owing to the unusual reactivity of sterically hindered amine borane complexes, we designed a catalytic system based on magnesium salts to perform a tandem dehydrogenation-dehydrocoupling between terminal alkynes and boranes. The reaction is providing pure alkynylboranes within few minutes at room temperature, with only two molecules of hydrogen as a by-product. Boron derivatives have long been used as key synthons in many organic transformations. [1] Among those, alkynylboronates [2] are no exceptions and already showed interesting reactivity in the transition metal-catalyzed formation of carbon-carbon [3] or carbon-heteroatom [4] bonds. Their synthesis is based on the C(sp)-H activation using a stoichiometric base or more recently, organometallic catalysis. The catalytic addition of silver-alkynide to iPrO-Bpin has been reported in 2014, [5] and the first dehydrocoupling using Ir/Pd-pincer complexes [6] was described only in 2013. Indeed, if many reports [7] followed pioneering works by Smith, [8] Hartwig [9] on C-H borylation, these methods are limited to C(sp 2)-H and C(sp 3)-H activation, and only a few reported C(sp)-H dehydrocoupling. In addition to Ozerov seminal paper, it has been shown that dehydrocoupling can be catalyzed by Zn(OTf)2 [3, 10] , NHC-Zn, [11] (CAAC)CuX [12] or Fe(OTf)2; [13] the borylating agent being pinacolborane (HBpin) or 1,8-diaminonaphthalenylborane (HBdan). Earth-abundant metal catalysis has recently gained major interest, including catalysis using group 2 organometallic complexes. [14] In all previously described cases, however, the reaction between a borane and earth alkali complexes resulted in the formation of metal-hydrides that subsequently reacted with terminal alkynes via hydrometallation. The following transmetallation to the boron would then lead to alkenylboranes, resulting from the formal hydroboration of the triple bond. This mechanism is highly represented in the literature, with transition metal such as Co [15] or Fe [16] , but also Al [17] ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
hal-02988447; https://hal.archives-ouvertes.fr/hal-02988447; https://hal.archives-ouvertes.fr/hal-02988447/document; https://hal.archives-ouvertes.fr/hal-02988447/file/AlkynylBorane-ManuscriptHALpdf.pdf |
| DOI: |
10.1002/chem.201905772 |
| Availability: |
https://hal.archives-ouvertes.fr/hal-02988447; https://hal.archives-ouvertes.fr/hal-02988447/document; https://hal.archives-ouvertes.fr/hal-02988447/file/AlkynylBorane-ManuscriptHALpdf.pdf; https://doi.org/10.1002/chem.201905772 |
| Rights: |
info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.BC84DB64 |
| Database: |
BASE |