Aluminum halides reactions with

Aluminum continued) halides, reaction with dechlorine monoxide, 5 52... 

The CO insertion reaction is strongly accelerated by Lewis acids such as alkali cations, protons , or aluminum halides, consistent with the hypothesis that the presence of Lewis acids increases the partial positive charge on the coordinated carbon... 

Aluminum halides react with water in a highly exothermic reaction. 

Preparation of Highly Reactive Aluminum and Reaction with Aryi Halides... 

The second general method is the aluminum halide-catalyzed reaction of acid halides with ethylene to give g-halo ketones which are subsequently converted to ketals. ... 

Friedel-Crafts acylation An analogous reaction occurs when acyl halides react with benzene in the presence of aluminum chloride. The products are acylben-zenes. 

The compounds AlYX are best prepared by direct reaction between the respective aluminum halide and chalcogenide in a sealed ampoule at 350°C. The reaction is complete after 2 weeks. In the case of the iodides, a mixture of A1 and I2 (molar ratio 3 10) is used instead of AII3. Other preparative methods, such as the reaction of an aluminum halide with Zn or Cd chalcogenide, or with the chalcogen itself, are applicable to the bromide and chloride only, and give poor yields (15-20%) (158, 159, 266, 327, 328). 

To optimize the alkylation conditions, ferrocene was reacted with allyldimethyl-chlorosilane (2) in the presence of various Lewis acids such as aluminum halides and Group lO metal chlorides. Saturated hydrocarbons and polychloromethanes such as hexane and methylene chloride or chloroform were used as solvents because of the stability of the compounds in the Lewis acid catalyzed Friedel-Crafts reactions. The results obtained from various reaction conditions are summarized in Table IV. 

Disilenes readily add halogens14,66 and active hydrogen compounds (HX), such as hydrogen halides,63,66 alcohols, and water,27 63 as well as hydride reagents, such as tin hydride and lithium aluminum hydride.66 These reactions are summarized in Scheme 9. The reaction of the stereo-isomeric disilene (E)-3 with hydrogen chloride and alcohols led to a mixture of E- and Z-isomers, but the reaction with chlorine gave only one of the two possible stereoisomers, thus indicating that the former two reactions proceed stepwise while the latter occurs without Si—Si rotation. 

Hogeveen and co-workers <82JOC1909 83JOC4275> also reported the synthesis of tricyclic sulfinamides by the reaction of cyclobutadiene aluminum halide o complexes (65 or 66) with 53 at low temperature. Treatment of 65 or 66 with 53 at -60 °C resulted in the formation of 67 or 68 in 52% and 55% yields, respectively (Scheme 18). 

Tin alkyl hydrides can be prepared from the halides by the reaction with lithium aluminum hydride. 

Less clear is the sequence which leads to the formation of the active species in the case of catalysts prepared from zero-valent nickel complexes and aluminum halides or alkylaluminum halides (method C2). The catalytic properties of these systems, however—in particular, the influence of phosphines (76)—leaves no doubt that the active species is also of the HNiY type discussed above. In this connection, a recent electron spin resonance report that nickel(I) species are formed in the reaction of COD2Ni with AlBr3 (83 ), and the disproportionation of Ni(I) to Ni(II) and Ni(0) in the presence of Lewis acids (69) should be mentioned. 

The second pathway is represented by Eqs. (8)—(11). These reactions involve reduction of the Nin halide to a Ni° complex in a manner similar to the generation of Wilke s bare nickel (37, 38) which can form a C8 bis-77-alkyl nickel (17) in the presence of butadiene [Eq. (9)]. It is reasonable to assume that in the presence of excess alkyaluminum chloride, an exchange reaction [Eq. (10)] can take place between the Cl" on the aluminum and one of the chelating 7r-allyls to form a mono-77-allylic species 18. Complex 18 is functionally the same as 16 under the catalytic reaction condition and should be able to undergo additional reaction with a coordinated ethylene to begin a catalytic cycle similar to Scheme 4 of the Rh system. The result is the formation of a 1,4-diene derivative similar to 13 and the generation of a nickel hydride which then interacts with a butadiene to form the ever-important 7r-crotyl complex [Eq. (11)]. 

Glycosyl halides, a very important group of carbohydrate derivatives, are commonly prepared14 from per-O-acylated sugars by reaction with hydrogen halides or halides of aluminum or titanium. The selection of the method depends mainly on the anomeric configuration of the substrate, the kind of its O-acyl groups, and the stability of the product to be prepared. 

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