- Rational Preparation of Well-Defined Multinuclear Iridium-Aluminum Polyhydride Clusters and Comparative Reactivity
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We report an original alkane elimination approach, entailing the protonolysis of triisobutylaluminum by the acidic hydrides from Cp*IrH4. This strategy allows access to a series of well-defined tri- and tetranuclear iridium aluminum polyhydride clusters, depending on the stoichiometry: [Cp*IrH3Al(iBu)2]2(1), [Cp*IrH2Al(iBu)]2(2), [(Cp*IrH3)2Al(iBu)] (3), and [(Cp*IrH3)3Al] (4). Contrary to most transition-metal aluminohydride complexes, which can be considered as [AlHx+3]x-aluminates and LnM+moieties, the situation here is reversed: These complexes have original structures that are best described as [Cp*IrHx]n-iridate units surrounding cationic Al(III) fragments. This is corroborated by reactivity studies, which show that the hydrides are always retained at the iridium sites and that the [Cp*IrH3]-moieties are labile and can be transmetalated to yield potassium ([KIrCp*H3], 8) or silver (([AgIrCp*H3]n, 10) derivatives of potential synthetic interest. DFT calculations show that the bonding situation can vary in these systems, from 3-center 2-electron hydride-bridged Lewis adducts of the form Ir-H←Al to direct polarized metal-metal interaction from donation of d-electrons of Ir to the Al metal, and both types of interactions take place to some extent in each of these clusters.
- Camp, Clément,Del Rosal, Iker,Escomel, Léon,Jeanneau, Erwann,Maron, Laurent,Robin, Emmanuel,Soulé, Na?me,Thieuleux, Chloé
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- Aluminum Chloride Promoted Cross-Coupling of Trisubstituted Enol Phosphates with Organozinc Reagents En Route to the Stereoselective Synthesis of Tamoxifen and Its Analogues
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A new method for the stereoselective cross-coupling reaction of arylzinc chlorides with trisubstituted enol phosphates is described. The developed method requires aluminum chloride as a promoter, and the reaction conditions tolerate various functional groups. The observed reactivity pattern of trisubstituted enol phosphates was used for the stereoselective preparation of tamoxifen and its analogues.
- Kotek, Vladislav,Polák, Peter,Dvo?áková, Hana,Tobrman, Tomá?
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p. 5037 - 5044
(2016/10/26)
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- Tandem nucleophilic addition-Oppenauer oxidation of aromatic aldehydes to aryl ketones with triorganoaluminium reagents
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In the presence of pinacolone, the in situ prepared triorganoaluminium reagents reacted with aromatic aldehydes to give ketones in moderate to high yield. We propose that the products are formed via a tandem organoaluminium reagents addition-Oppenauer oxidation sequence. The Royal Society of Chemistry 2013.
- Fu, Ying,Yang, Yanshou,Hügel, Helmut M.,Du, Zhengyin,Wang, Kehu,Huang, Danfeng,Hu, Yulai
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supporting information
p. 4429 - 4432
(2013/08/23)
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