Trichloromethyl addition reactions

Bromotrichloromethane can also be used effectively in the addition reaction. Because of the preferential abstraction of bromine, a trichloromethyl unit is added to the less substituted carbon atom of the alkene ... 

The reactive intermediates under some conditions may be the carbenoid a-haloalkyllithium compounds or carbene-lithium hahde complexes.95 In the case of the trichloromethyl-lithium —> dichlorocarbene conversion, the equilibrium lies heavily to the side of tri-chloromethyllithium at —100° 96 The addition reaction with alkenes seems to involve dichlorocarbene, however, since the pattern of reactivity towards different alkenes is identical to that observed for the free carbene in the gas phase.97... 

When t-butyl or trichloromethyl radicals were bombarded with ethylene no detectable reaction occurred. The reaction of normal alkyl radicals, apart from ethyl, with ethylene cannot be studied directly because the e.s.r. spectra, of the initial and final radicals are virtually identical, but this difficulty could be overcome by using deuteriated ethylene. However, when the reaction of n-heptyl radicals with deuteriated ethylene was studied, no reaction occurred. As the deuteriated ethylenes are known to undergo addition reactions more readily than the protium analogue (Feld et al., 1962), the results indicate that alkyl radicals would not add to ethylene under the conditions of these experiments. The absence of reaction allows a lower limit of about 5 kcal rnole" (see earlier discussion VIIIA) to be placed on the addition of n-alkyl (apart from ethyl), t-butyl and trichloromethyl radicals to ethylene. 

Trichhromethylation of anhydrides. When the salt is decomposed in 1,2-di-mcthoxyethane in the presence of an olefinic anhydride, reaction occurs exclusively at a carbonyl group of the anhydride, apparently by the trichloromethyl anion precursor of the carbene, to give the trichloromethyl addition product. Yields are erratic, ranging from 80 to 8%. 

Yet another form of addition reaction is that of (trichloromethyl)phosphonic dichloride, as a consequence of its highly polarized C-Cl bonds, to buta-1,3-dienes in the presence of CuCl addition is 1,4, with the formation of (l,l,5-trichloropent-3-enyl)phosphonic dichlorides (139) as Z-E mixtures ". ... 

Miscellaneous Reactions. 1.2.1 Addition Reactions - A novel photochemical reaction of stilbene in carbon tetrachloride solution has been described. Irradiation of this system populates the first excited singlet state of stilbene which then abstracts a halogen from the solvent. The resulting radical pair composed of a trichloromethyl radical and (14) yields the products. 

Other routes giving access to caronic acid are shown in Reaction scheme 116. The easiest one seems to be the sulfurane addition to mesityl oxide (as shown in Reaction scheme 63) and subsequent haloform reaction [283] to give trans caronic acid 186, Thermal treatment [283] or a catalytic process in acetic anhydrid [286], yields the ds-caronic 187 anhydride as a very interesting chemical. For example, on treatment with sodium trichloroacetate in acetonitrile, it traps the trichloromethyl anion (Reaction... 

Keywords N-Phosphinoyl benzaldimines, trimethyl(trichloromethyl)silane, tetrhydrofuran, room temperature, nucleophilic addition reaction, N-phosphinoyl-a-(trichloromethyl) benzylamines... 

In conclusion, five-membered metallacycles of titanocene and zirconocene are convenient starting materials for the construction of five-membered car-bocyclic compounds. The formation of five-membered carbocycles can be accomplished by addition reactions (or insertion reactions) of a variety of electrophiles, such as CO, RCN, RNC, bis(trichloromethyl)carbonate, allenyl carbenoids, halogencarbenoids, aldehyde, acyl chlorides, propynoates, and iodopropenoatesthe to the five-membered metallacycles. 

The catalytic conditions (aqueous concentrated sodium hydroxide and tetraalkylammonium catalyst) are very useful in generating dihalo-carbenes from the corresponding haloforms. Dichlorocarbene thus generated reacts with alkenes to give high yields of dichlorocyclopropane derivatives,16 even in cases where other methods have failed,17 and with some hydrocarbons to yield dicholromethyl derivatives.18 Similar conditions are suited for the formation and reactions of dibromocar-benc,19 bromofluoro- and chlorofluorocarbene,20 and chlorothiophenoxy carbene,21 as well as the Michael addition of trichloromethyl carbanion to unsaturated nitriles, esters, and sulfones.22... 

We see that the effect of multidipole interaction plays an important role in all reactions of abstraction and addition of polar reactants. This interaction can increase or decrease the activation energy of the reaction. However, the multidipole interaction does not influence the reactions of nonpolar trichloromethyl radicals with mono- and polyatomic esters due to the nonpolar character of the attacking radical [89]. 

Gedanken and colleagues136 investigated the Diels-Alder reactions of trichloromethyl allenyl sulfoxides 203 and cyclopentadiene under ultrasound irradiation. Allenes 203 are generally very sluggish in reactivity. However, when ultrasound was applied, the reactions of allenes 203 with cyclopentadiene were completed within 2 hours (equation 57). Mixtures of endo (204) and exo (205) isomers were obtained in all instances. When the y-position of the allenyl sulfoxides was substituted, additional mixtures of E and Z isomers were obtained. 

Conjugated ketones and esters generally react with chloroform under basic conditions by Michael-type addition of the trichloromethyl anion to the C=C bond or by insertion of dichlorocarbene into the C=C bond, depending on the substitution pattern of the conjugated system (see Sections 6.4 and 7.3). The corresponding reaction with bromoform under basic conditions produces 1,1-dibromocyclopropanes. 

Irradiation of diazo 21d in carbon tetrachloride gave, in addition to 72 (R = Me) and 73, the 3-chloro-3-trichloromethyl-l-methyloxindole (76a) (64JOC3577). Since the photolysis in carbon tetrachloride under comparable conditions produces, in the primary step, CCI3 radicals and chlorine atoms (63JOC3442), in the formation of 76a and probably in the reaction with oxygen to give 74, the carbene 71 shows biradical properties in the... 

A. Pyrrol-2-yl trichloromethyl ketone. In a 3-1. three-necked round-bottomed flask equipped with a sealed mechanical stirrer, a dropping funnel, and an efficient reflux condenser with a calcium chloride drying tube are placed 225 g. (1.23 moles) of trichloroacetyl chloride and 200 ml. of anhydrous ether. The solution is stirred while 77 g. (1.15 moles) of freshly distilled pyrrole in 640 ml. of anhydrous ether is added over 3 hours (Note 1). The heat of reaction causes the mixture to reflux during the addition. Following the addition, the mixture is stirred for 1 hour, and then 100 g. (0.72 mole) of potassium... 

---