5.5- dichloro adduct with

Cycloocta-2,5-diene yields the mono adduct with dimethylvinylidene carbene ( 19%) [156]. With dichloro- and dibromocarbene, the syn- and cmh-bis-adducts are obtained in a ratio which favours the syn-isomer [55, 104] whereas, with bromochlorocarbene, the mono-adduct is reported to be the major product (55%) with only 9% of the bis-adduct [142]. In contrast, cyclo-octatetraene is converted into the mono-, syn-1,2 5,6-bis-, tris-, and tetra-adduct with dichlorocarbene depending on the reaction conditions [4, 17, 25, 55] and the 1,2 5,6-bis-adduct with... 

Conjugated dienes yield mono-adducts with dihalocarbenes at the more electron-rich C=C bond further reaction at the less reactive bond may also occur [e.g. 4,8,19, 23, 31, 37, 49, 62, 69, 94]. Cycloheptatriene yields the syn- and nnti-1,2 5,6-bis-adducts (14.5 and 22.9%) and the syn-1,2 5,6-ann -3,4-tris-adduct with dichloro-carbene [62], The facile reaction of cyclopropylethenes with dihalocarbenes produces dicyclopropyl compounds [53, 117]. Isoprene reacts with chloro(phenylthio)carbene across the more reactive 1,2-bond (51%) [146]. 

No information was located for the mechanism of inhalation, oral, or dermal absorption of 3,3 -dichloro-benzidine in humans or animals. Also, no information was located for the mechanism by which 3,3 -dichlorobenzidine is transported in the blood. However, a studies in rats have shown that 3,3 -dichlorobenzidine forms adducts with hemoglobin (Bimer et al. 1990 Joppich-Kuhn et al. 1997), indicating that at least a small amount of the chemical is associated with red blood cells. 

The absence of an EPR signal in solution or in the solid state is indicative of a singlet ground state for the diradical ( BuBP Pr2)2- An indication of the radical character of this derivative is provided by a variety of facile oxidative addition reactions (Scheme 9.12). " For example, the treatment of ( BuBP Pr2)2 with diphenyl diselenide (or elemental selenium) produces a bicyclic compound in which a selenium atom bridges the two boron atoms. Trimethyl tin hydride reacts rapidly with ( BuBP Pr2)2 to give the trans adduct. Finally, ( BuBP Pr2)2 is slowly oxidised by deuterated chloroform to produce a R,R -dichloro adduct as a mixture of cis and trans isomers. 

If the dichloro adduct of 1-methylarsenane is heated it loses methyl chloride with the formation of 1-chloroarsenane (77) (32CB409). The dibromo adduct reacts similarly (16BSF151,16BSF290). 1-Chloroarsenane can be reduced to the parent arsenane (78) using the reaction conditions shown in Scheme 16. This compound is readily oxidized in air to the arsenic acid (79) (57ZN(B)135). This arsenic acid is also formed from the oxidation of the 1,1-diarsine oxide (80) (34CB730). 

Dichloro(cyclopentadienyl)methyltitanium, CpTi(CH3)Cl2 (1). The reagent is prepared by reaction of CpTiCl3 with (CH3)2Zn (71% yield).15 Unlike many organotitanium reagents, 1 is heat-stable. As expected, 1 forms adducts with aldehydes at room temperature but reacts only slowly with ketones even at 50°. The reaction with benzoyl chloride is slow and requires 2 equiv. of 1 to afford 2-phenyl-2-propanol (50% yield).16... 

Some solid-state reactions have been reported for the chlorination of alkenes. For example, styrene upon reaction with a mixture of IOB and hydrogen chloride-treated silica gel gave the dichloro adduct (65%) since no solvent was present, it was essential to use efficient cmshing and grinding [12],... 

Alkynes reacted with (dichloroiodo)benzene under free radical conditions to give trans- 1,2-dichloro adducts. The stereoselectivity of the reaction was much better than with elemental chlorine yields were also improved. An example is provided by the chlorination of cyclopropylacetylene under photochemical conditions [11] ... 

Phenylselenyl chloride adds to alkenes in a stereoselective trans manner950. The adduct is oxidized by chlorine and the seleno moiety is displaced by chloride with inversion of the configuration to yield the cis dichloro adduct (equation 142)951. 

As mentioned above, manganese peroxidase was unable to oxidize 2,7-dichloro-dibenzo-p-dioxin. Nevertheless, in the presence of polyunsaturated fatty acids, manganese peroxidase is able to form adducts with 2,7-dichlorodibenzo-p-dioxin [119]. 

The product is the 1,2-dichloro ring adduct with 83 per cent cis and 17 per cent trans isomers. 

Antimony(V) chloride (SbQj) and molybdenum(V) chloride (MoCls) can react spontaneously with alkenes to give predominantly the corresponding c/s-1,2-dichlorides (equation 11). The reaction probably proceeds through a successive insertion and reductive elimination sequence. The chlorination of butadiene with SbCls and copper(II) chloride results preferentially in the formation of (Z)- and ( )-1,4-dichloro adducts, while the reaction with chlorine gives an 1 1 mixture of 1,2- and 1,4-adducts, as shown in Table 2 and equation (12). The formation of (Z)-l,4-dichloro-2-butene may be ascribed to a transition state as shown in Scheme 3. 

Dithioacetic acid derivatives add to 1,4-benzo- or 1,4-naphthoquinones to give, after oxidation of the adduct with silver oxide or chloranil, the quinones 217 and 218 (69LA103). Quinones 218 were prepared also from 2,3-dichloro-1,4-naphthoquinone and salts of dithiocarbamic acids (51JA3459) and those of type 219 by oxidation of the corresponding hydroquinones. From reduction potentials and the semiquinone formation constants, it was concluded that their anion radicals are thermodynamically stable (86CC1489). 

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