Lewis adds 608 Subject

As mentioned above, the ability of TiCl4 (OR) to function as a Lewis add decreases as n increases. Few adduct complexes of Ti(OR)4 are known, although Ti2(OEt)8 en, Ti2(OPri)8-en and Ti(OPri)4-en have been reported,14 but these complexes almost completely dissodate in solution. However, Ti(OPh)4 readily forms 1 1 adducts with PhOH, NH3, NH2Me, NHMe2, NMe3, py, dioxane, PhNH2, Me2CO- These complexes have been the subject of a review.62 The difference in the behaviour of the Ti(OPh)4 to the Ti(OR)4 (R = Me, Et) towards Lewis bases is undoubtedly related to the monomeric, and thus the coordinatively unsaturated, nature of the phenoxides in solution. 

A more vital application is to discern how reinforcement surface treatments improve adhesion to thermoplastic matrices. Since the nonreactive nature of thermoplastics normally precludes interfacial covalent bond formation, secondary bonding forces, such as London dispersion interactions and Lewis add/base interactions, may play a major role in these drcumstances. These secondary binding forces are subject to surface energetics analysis. 

The use of BF3-Et20 to accentuate the reactivity of otherwise sluggish cuprates toward 1,2-additions is also the subject of a recent report by Knochel. Functionalized lower order cyanocuprates incorporating Znl+ as the gegenion in place of Li+ or MgX+ readily add to aldehydes at low temperatures provided excess Lewis acid is present (Scheme 9). Isolated yields of products are very good, and the observation that ketones do not react under similar conditions adds an element of chemospecificity to this method. 

The Friedel-Crafts acylation, the reaction of an aromatic compound with an acid chloride and a Lewis acid (such as AICI3), adds an acyl group to the aromatic ring to give an aromatic ketone product. like the previously discussed alkylation reaction, it involves a strongly electrophilic carbocation (called an acylium ion), but this carbocation is not subject to rearrangement since it is stabilized by resonance. 

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