Syntheses of polyaluminium compounds by hydroalumination reactions, chelating Lewis acids possessing two and four coordinatively unsaturated aluminium atoms

Poly‐Boron, ‐Silicon, and ‐Gallium Lewis Acids by Hydrometallation of 1,5‐ and 1,8‐Dialkynylanthracenes

“…Prominent examples include mercury,1 tin2 and silicon,3 for example, the trisilacyclohexane derivative reported by Brondani et al3a or the Si‐based crown ether analogue reported by Jung and Xia 3b. Remarkable progress in the field of poly‐Lewis acids based on aluminium4 and gallium [4e–4g,5] has been achieved by Uhl and co‐workers with hydroalumination4d–4f and hydrogallation reactions employing dialkylgallanes [4e,4f,5a–5c] and dichlorogallane as reagents,5d–5g respectively. The synthesis of dichlorogallane (HGaCl 2 ) 2 6 and its application in the hydrogallation of unsaturated substrates7 was first investigated by Schmidbaur and co‐workers.…”

Facile Synthesis of Aluminum‐Bridged [3,3,3]Cyclophanes by Hydroalumination

“…A preferred cis addition was postulated owing to the constitutions of the finally isolated hydrocarbons. [1] As was shown by our group only recently, [4,5] silyl-substituted alkynes gave the predicted products of hydroalumination with a dialkylaluminum group attached to that carbon atom that also bears the trimethylsilyl group (1 and 2 in Scheme 1). This particular constitution may be favored by two reasons.…”

Hexadentate Poly‐Lewis Acids Based on 1,3,5‐Trisilacyclohexane

“…PLA with a rigid backbone and a defined distance between the reactive atoms can be obtained by direct multiple metalation of various types of compounds, including aromatic compounds such as benzenes, [6] biphenylenes, naphthalenes [7] or methanes [8] . Examples of poly‐Lewis acids based on these four classes of molecules are bis‐ and tris(dimethylgallyl)benzenes [6a] or a series 9,10‐diboraanthracene derviatives, the 1,8‐bis(dimesitylboryl)‐biphenylene [5a] and the dialuminium compounds that are bridged by a methylene ((Me 3 Si) 2 HC) 2 AlCH 2 Al(CH(SiMe 3 )) 2 [8a] or dicarboxynaphthalene units [7] . Some of these representatives were successfully used in the molecular recognition for chelating complexation of small anions (e. g. halides, [6b] cyanide, [5a] nitrate [8a] ) and neutral guest molecules (e. g. dimethyl sulphoxide, [8d] pyridazine [8c] ), catalytical [6d; 9] or optical applications [6e,f] …”