A,co-Dihaloalkanes

Thermolysis of the dicarbamic acid silyl ester (CH2 N[SiMe3]C02SiMe3)2) gives the 1,3-diazetane derivative 26 <96JOM93>. Alkylation of the 1,3-dithietane tetraoxide 27 with a,co-dihaloalkanes yields the dispiro compounds 28 (n = 1-4) <95ZOR589>. The first 1,2-dithiete S-oxide 29 is reported <95TL8583>. 

Janssen DB, D Jager, B Witholt (1987) Degradation of -haloalkanes and a,co-dihaloalkanes by wild-type and mutants of Acinetobacter sp. strain GJ70. Appl Environ Microbiol 53 561-566. 

Gusarova, N.K., Shaikhudinova, S.I., Dmitriev, V.I., Malysheva, S.F., Arbuzova, S.N., and Trofimov, B.A., Reaction of red phosphorus with electrophiles in superbasic systems. VII. Phospholanes and phosphorinanes from red phosphorus and a,co-dihaloalkanes in a single preparative step, Zhur. Obshch. Khim., 65, 1096, 1995. 

The conversion of S-alkyl isothiouronium salts into thioethers is aided by the addition of a phase-transfer catalyst (4.1.4.E) [30]. Similarly, a,co-dihaloalkanes are converted in a one-pot reaction into bis-sulphides (> 90%) via the isothiouronium salts (Scheme 4.3) [31]. 

A superior and relatively versatile procedure for the synthesis of unsymmetrical dialkyl thioethers, which avoids the unattractive direct use of thiols, utilizes the stable l-alkylthioethaniminium halides, which are readily obtained from thioacet-amidc [32] (Scheme 4.4). The reaction has also been used for the synthesis of alkyl aryl thioethers from activated aryl halides [33], but it cannot be used for the synthesis of cyclic thioethers, as polymeric sulphides are formed from a,co-dihaloalkanes. A similar sequence to that which leads to the thioethers has been used for the synthesis of S-alkyl thioesters [34] (see 4.1.26). 

The catalysed A/-alkylation of the potassium salt of sulphoximines in l, 2-dimethoxyethane produces yields in excess of 90% [48]. Similarly, azacrown ethers have been synthesized by alkylation of bis(tosyIamino)alkyl ethers under catalysed basic two-phase conditions [49] (Scheme 5.12). The yields of the cyclic products (Table 5.24) are influenced by the choice of the alkali metal hydroxide employed, suggesting that there is a degree of template control in the ring closure step. This is not the case in the analogous reaction of p-toluenesulphonamide with a, co-dihaloalkanes [50], which leads to the formation of a mixture of l l and 2 2 cyclic products... 

An important application of alkylation with di- and polyhalides is cyclialkylative ring formation. Of different a,co-dihaloalkanes studied, 1,4-dichlorobutane was shown to react at exceptional rate and with least rearrangement.143 This was rationalized in terms of participation by the cyclic chloronium ion 29 formed with anchimeric assistance by the second chlorine atom in the molecule ... 

We have shown, however, that a significant number of monohalogen-oalkyl transition metal compounds have now been prepared, many of them in the last decade. A variety of routes have been used to synthesize these compounds, but the most common ones are (1) the reaction of an alkoxyalkyl compound with anhydrous HX (X = Cl, Br, or I), (2) the reaction of a nucleophilic transition metal compound with a dihaloalkane, and (3) the insertion of a methylene group into a metal-halogen bond. The most common route to the co-halogenoalkyl complexes is by reaction of an anionic metal species with the a,co-dihaloalkane. These monohalo-... 

It has been initially proposed that the electrochemical formation of cycloalkanes from a,co-dihaloalkanes involves a concerted mechanism in which a two-electron cleavage of one C-X bond to form a carbanion takes place simultaneously with the displacement of the second halogen. Later, Fry and Britton questioned this mechanism and suggested a... 

Synthesis of cycloalkanecarboxylic acids from a,co-dihaloalkanes and diethyl sodiummalonate (see 1 st edition)... 

The reaction of phosphorus(III) acid esters with a,co-dihaloalkanes at elevated temperature, proceeding via formation of co-haloalkylphosphonate or co-haloalkyl-phosphinate in the result of the Arbuzov-Michaelis reaction, is one of the first known synthetic approaches to 2-oxo-l,2-oxaphosphacyclanes 62 (Scheme 30) [1, 2, 51, 52],... 

Von Braun1051 prepared long-chain a ,co-dihaloalkanes from the corresponding bisphenyl ethers, which are accessible from aryl co-haloalkyl ethers by a Wurtz synthesis (a). 

The later stages of reactions involving a,co-dihaloalkanes and related compounds may be accompanied by cyclization, particularly at higher temperatures (equation 8) The two-stage reactions between trialkyl phosphites and 1,4-dibromo- or 1,5-dibromoalkanes give rise to 1,2-oxaphosph(V)orinanes (57) n = 1) or l,2-oxaphosph(V)epanes (57) n -2) accompanied by monodehydrobromination during the formation of a linear ester. 

Mubarak, M.S. and D.G. Peters (1995). Homogeneous catalytic reduction of a, co-dihaloalkanes with electrogenerated nickel(l) salen. J. Electroanal. Chem. 388(1-2), 195-198. 

Friedel-Crafts reactions of a,co-dihaloalkanes with linear polystyrene afforded a new type of polymer which, when converted into a polymeric quaternary salt, showed high swelling properties and reactivity... 

Polyacrylonitrile hollow fibers fabricated at Gulf South Research Institute were used. Their hydraulic permeability was 9x 10 cm/s atm, the wall thickness 50 /x, the inside diameter 200 microns and the wall micropore diameter about 100 A. Hollow fibers (150) assembled in bundles with a total surface area of 140 cm were washed first with water, and then with methanol and dried by passing nitrogen gas through them for one hour. They were immersed in a mixture of 4-VP and a,co-dihaloalkane (2 1 molar). The reaction was permitted to proceed for 10 days in case of dibromo ethane and 2 days in the case of dibromohexane. A cross section of a typical fiber is shown in Figure 5. 

Synthesis of alicyclic compounds from a,co-dihaloalkanes and compounds containing active methylene groups in the presence of sodium ethoxide ... 

Copper was used in carbon-carbon bond formation reactions for the first time in 1904 [140] in the well-known Ullmann reaction which involved aromatic halides. Very recent work has reported the use of activated copper (Cu ) in homo-coupling and cyclization reactions of a, co-dihaloalkanes [141],... 

It should be added that the nickel(0)-dipyridyl (dipy) complex is a powerful reagent for converting a,co-dihaloalkanes to cycloalkanes (Takahashi et al, 1974). 

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