Potassium Aluminyl Promoted Carbonylation of Ethene. (24th February 2022)

• Record Type: Journal Article
• Authors: Evans, Matthew J.; Neale, Samuel E.; Anker, Mathew D.; McMullin, Claire L.; Coles, Martyn P.
• Is Part Of: Angewandte Chemie. Volume 134:Number 16(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-24
• Subjects: Aluminyl Anions -- Bimetallic Complexes -- Carbonylation -- Hydrogen-Shift -- Metallacycles; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202117396
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The potassium aluminyl [K{Al(NON Dipp )}]2 ([NON Dipp ] 2− =[O{SiMe2 NDipp}2 ] 2−, Dipp=2, 6‐ i Pr2 C6 H3 ) activates ethene towards carbonylation with CO under mild conditions. An isolated bis‐aluminacyclopropane compound reacted with CO via carbonylation of an Al−C bond, followed by an intramolecular hydrogen shift to form K2 [Al(NON Dipp )( μ ‐CH2 CH=CO‐1κ 2 C 1, 3 ‐2κ O )Al(NON Dipp )Et]. Restricting the chemistry to a mono‐aluminium system allowed isolation of [Al(NON Dipp )(CH2 CH2 CO‐κ 2 C 1, 3 )] −, which undergoes thermal isomerisation to form the [Al(NON Dipp )(CH2 CH=CHO‐κ 2 C, O )] − anion. DFT calculations highlight the stabilising influence of incorporated benzene at multiple steps in the reaction pathways. Abstract : Metal‐promoted carbonylation of alkenes is established for d ‐block metals, whilst prior work with aluminium has been limited by reversible C=C coordination and decomposition of CO insertion products. This work shows how the aluminyl anion allows the non‐reversible carbonylation of ethene using carbon monoxide under mild conditions. A bimetallic pathway involving an intramolecular 1, 2‐hydrogen shift was identified and supported by DFT calculations.