Trichloride complexes

The reaction is initiated by formation of a donor-acceptor complex 4 from acyl chloride 2, which is thereby activated, and the Lewis acid, e.g. aluminum trichloride. Complex 4 can dissociate into the acylium ion 5 and the aluminum tetrachloride anion 4 as well as 5 can act as an electrophile in a reaction with the aromatic substrate ... 

The Lewis acid mediated addition of allylic tin reagents to nitroalkenes has been reported. The condensation reaction of tributyl[(Z)-2-butenyl]tin(IV) with (E)-(2-nitroethenyl)benzene or (L)-l-nitropropene catalyzed by titanium(IV) chloride proceeded with modest anti diastereoselectivity. Poorer diastereoselection resulted when diethyl ether aluminum trichloride complex was employed as the Lewis acid 18. 

Me3tacn)CrX3 (X = Cl, CF3SO3, CN). The preparation of the trichloride complex is adapted from previous reports,while the preparations for the other precursors represent modifications of those described for the analogous (tacn)-containing complexes. 

At the time of our investigation the only known coordination compounds of chlorophosphines (aside from phosphorus trichloride complexes) were the nickel-(0) compounds, tetrakis(methyldichlorophosphine)nickel-(0) (20) and tetrakis-phenyldichlorophosphine) nickel- (0) (17). Tetrakis (methyldichlorophosphine) -nickel-(0) is noteworthy in that it represents a still rare example of the direct reaction of a ligand with an elemental transition metal to give a complex, while tetrakis (phenyldichlorophosphine) nickel- (0), like tetrakis (trichlorophosphine) -nickel-(0), was obtained readily via the carbonyl. AD chlorophosphine-nickel-(O) complexes, including the phosphorus trichloride complex, Ni(PCl3)4, are compounds relatively stable in the atmosphere, but show poor stability in almost any organic solvent, even under strictly anaerobic conditions. 

Numerous adducts of MX4 with nitrogen, phosphorus, arsenic, oxygen and sulfur donors have been obtained, mainly for niobium with X = CI or Br7 (Tables 29-33). The absence of MF4 adducts, except for [NbF4(py)2],511 may be due less to their instability than to a lack of investigations. An ill-defined fluoro trichloride complex, [NbCl3F(MeCN)2.65], has also been reported.512... 

As indicated in Scheme 27, indoles may be alkylated by their acid-catalyzed reaction with alcohols. Similarly, r-butylation of pyrroles has been effected by the acid-catalyzed reaction with t- butyl acetate (B-77MI30502), and the diarylmethylation of 1-methylpyrrole from the acid-catalyzed reaction with the chromium trichloride complex of the diarylcarbinol has been described (78JA4124). The alkylation of indoles by alcohols in the presence of the aluminum alkoxide and Raney nickel appears to be efficient for the synthesis of 3-substituted indoles, but is less successful in the alkylation of 2-methylindole (79JHC501). The corresponding isopropylation of pyrrole produces 2,5-diisopropylpyrrole and 1-isopropylpyrrolidine, as the major products (79JHC501). 

S. Fuji, Ethylene Polymerization with the Catalysts of One- and Two-Component Systems Based on Titanium Trichloride Complex, in Ref. 9, p. 135. 

The electrophile, an acyl cation, is generated in a manner similar to that outlined in Figure 17.4 for the generation of the carbocation electrophile from an alkyl halide. First the Lewis acid, aluminum trichloride, complexes with the chlorine of the acyl chloride. Then A1C14 leaves, generating an acyl cation. The acyl cation is actually more stable than most other carbocations that we have encountered because it has a resonance structure that has the octet rule satisfied for all of the atoms ... 

Unusual nitrogen-stabihzedZr trichloride complex bearing pendant ligand (see Pendant Groups) can be obtained by... 

Most of the complexes have well defined melting points. They appear to be monomeric in solution . An interesting method for the preparation of thiazolidine-2-thione complexes of aryl tellurium trichlorides is the addition of the tellurium compound to a melt of the ligand kept at 110°. Complexes with 1 1, 1 2, and 1 4 stoichiometries (Te-compound ligand) were obtained after recrystallization from dry methanol. Phenyl tellurium trichloride complexes with thiourea appear to form only when an organic solvent is used as the reaction medium in aqueous media the trichloride is reduced to the monochloride that is isolated as the thiourea adduct . 

Many mechanisms in organic chemistry start with an acid/base reaction. This may be just a simple Bronsted-Lowry protonation of a hydroxyl group, which results in the activation of a C-OH bond or it may be a Lewis acid/base reaction as, for example, when aluminium trichloride complexes with a halogenoalkane in the first step of the Friedel-Crafts reaction. In each case, the initial intermediate usually reacts further and leads to the desired product. In inorganic chemistry, the acid/base reaction may be all that is of interest, e.g. the treatment of a carbonate with an acid to liberate carbon dioxide. However, it is unusual in organic chemistry for the acid/base reaction to be an end in itself. It is for this reason that acid/base characteristics are normally considered as a property of the molecule, similar to the nucleophilic and electrophilic properties to which they are closely related, rather than as a fundamental reaction type as is the case in inorganic chemistry. 

Alkylated mono-Cp trichloride complexes Cp MCl3, Cp = l /l-Bu CsH M = Zr 288, Hf 289, and Cp = EtsCs, M = Zr 290, were synthesized by salt metathesis (Scheme 60). These compounds can be readily converted into the corresponding benzyl derivatives Cp Zr(CH2Ph)2Cl 291 or Cp Zr(CH2Ph)3 2 92.229 Refluxing a mixture of lithium... 

The salt metathesis reaction of ZrCU and the lithium tetramethylcyclopentadienide bearing the 2-methoxyethyl or the 2-methylthioethyl donor sidearm produces half-sandwich zirconium trichloride complexes 445 (Equation (34)).314,315 As expected, these complexes show monomer-dimer dynamic behavior in solution and exist as doubly chloro-bridged dimers in the solid state. 

Condensation of the boron trichloride complex of N-methylanllines with aromatic aldehydes affords o-aminobenzhydrols in moderate yields. Somewhat lower yields of the corresponding ketones are obtained by condensing the adduct obtained from aniline itself with nitriles in the presence of Aid-... 

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