Aluminum Tris(2,6-diphenylphenoxide) (ATPH) as an Extremely Selective Activator of Less Hindered Aldehyde Carbonyls

Cage‐Shaped Borate Esters with Tris(2‐oxyphenyl)methane or ‐silane System Frameworks Bearing Multiple Tuning Factors: Geometric and Substituent Effects on Their Lewis Acid Properties

“…This result can be explained by the steric effects of the ortho-phenyl substituent that prevented access of the bulky substrate to the metal center. [35,36] The use of 1 eB with acetonitrile as the solvent showed a 6.49-fold increase compared to 1 aB (entries 3 and 4). The coordinative solvent somewhat retarded complexation with the substrate aldehyde, and, hence, the selectivity was enhanced.…”

The crystallographic observation of molecular lithium oxide: synthesis and solid-state structure of [Me2AlN(2-C5H4N)Ph]2(O)Li2·2THF†

“…Although the presence of trace moisture cannot be entirely ruled out, previous work with lithium aluminates, 26,27 the isolation and characterisation of 2 [inconsistent with LiOH contamination of the (Me 3 Si) 2 NLi substrate], and the absence of any isolable aluminoxane 28,48 hydrolysis products, points to molecular oxygen being responsible for the formation of Li 2 O. NMR spectroscopic investigations into the formation of 3 are ongoing and will focus particularly on the nature of any byproducts since the observation of (Me 3 Si) 2 NH would clearly suggest the presence of moisture whereas the reaction of O 2 requires generation of the hydrazine [(Me 3 Si) 2 N] 2 . 22 Also of mechanistic interest is the observation that neither the amidoalane 43 component of 3 nor the lithium aluminate 26,27 2 has demonstrated thermodynamic oxo-insertion into Al-C bonds.…”

“…123.13 (18) C26-N5-Al2 120.8 (2) that typically observed in (LiO) 2 rings. 6,38 Compound 3 can therefore be regarded as the lithium salt of an oxo-bridged bis-(aluminate).…”

“…6 Further studies into the chemistry of mixed Li-Al systems have led to the report that Me 2 AlN(2-C 5 H 4 N)Ph 1 reacts with Bu t Li to afford hydridecontaining clusters 7 whose formation is critically dependent on the use of organolithium precursors capable of β-eliminating LiH. 8 While this view was supported by the observation that the treatment of 1 with MeLi affords [Me 3 AlN(2-C 5 H 4 N)Ph]Li, 9 we wish to report here that the analogous treatment of 1 with (Me 3 Si) 2 NLi affords a simple lithium aluminate 2. Moreover, whereas previously reported oxygen scavenging by lithiated homometallic OMe]Li} 2 has lately been isolated and fully characterised 26 with oxo-insertion into Al-C bonds observed.…”

Bulky Aluminum Lewis Acids as Novel Efficient and Chemoselective Catalysts for the Allylation of Aldehydes

“…11 It has been reported that ATPH is able to discriminate between structurally similar aldehydes and thereby facilitates the selective functionalization of a less hindered aldehyde as it has been demonstrated for hetero-Diels-Alder and aldol reactions. 12 Recently it has been shown that Diels-Alder reactions between a carbonyl and diene due to encapsulation of both substrates by ATPH can be achieved. 13 In all the reported examples stoichiometric amounts or even an excess of ATPH (up to 2.2 eq.)…”