Addition of the trichloromethyl

The /rans-fiised decalin system is conformationally rigid, and the stereochemistry of the product indicates that the initial addition of the trichloromethyl radical is from the axial direction. This would be expected on stereoelectronic grounds, because the radical should initially interact with the n orbital. The axial trichloromethyl group then shields the adjacent radical position enough to direct the bromine abstraction in the trans sense. 

TABLE 4. Relative rate constants for the addition of the trichloromethyl radical to substituted styrenes and butadiene in BrCCl3 at 80 °C12... 

A combined -cyclodextrin quatemary ammonium salt catalyst promotes the addition of the trichloromethyl anion to aromatic aldehydes and enhances the yield of the a-hydroxy acid [7],... 

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. 

The radical reaction of carbon tetrachloride with aliphatic double bonds involves addition of the trichloromethyl radical to the double bond, followed by chlorine atom abstraction from carbon tetrachloride by the intermediate radical to give the product. After the addition of the trichloromethyl radical to /3-pinene, a fragmentation occurs prior to formation of the product. 

Since the cyclopropanation is rather slow, it is postulated that the formation of dichlorooxirane goes via the addition of the trichloromethyl anion to the carbonyl group, then the cyclization of the adduct the intermediate oxirane 11 was isolated after 30-40% conversion of ketone. 

The precursor 66 of the DATE triflate reagent 69 can only be synthetized from 61 by bromination with NBS and subsequent hydrolysis, or from 62 by addition of the trichloromethyl carbanion. The attempted preparation of 66 from 63 and 64 via 65 does not succeed. Presently we are exploring the use of the DATE group as a protective group for other functions than the 5 -hydroxy group of nucleosides (see above). 

The mechanism of the condensation in Part D probably involves thioformylation of the metallated isocyanoacetate followed by intramolecular 1,1-addition of the tautomeric enethiol to the isonitrile. This thi2izole synthesis is analogous to the formation of oxazoles from acylation of metallated isonitriles with acid chlorides or anhydrides. " Interestingly, ethyl formate does not react with isocyanoacetate under the conditions of this procedure. Ethyl and methyl isocyanoacetate have been prepared in a similar manner by dehydration of the corresponding N-formylglycine esters with phosgene and trichloromethyl chloroformate, respectively. The phosphoryl chloride method described here was provided to the submitters by Professor U. Schollkopf and is based on the procedure of Bohme and Fuchs. The preparation of O-ethyl thioformate in Part C was developed from a report by Ohno, Koi/.uma, and Tsuchihaski. " ... 

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... 

Enamine 204 reacts with cyanogen bromide with an unexpected result an aminocyanopyrimidine derivative 206 is the product. The reaction proceeds by the addition to the primary amino group with formation of compound 205 followed by cyclization and replacement of the trichloromethyl group by cyano group [85JCS(P1)1499],... 

Fmoc-peptide-resin was deprotected with 20% piperidine/DMF (2 min+8 min). After washing, the resin was treated with dry THF (1 mL) for 15 min. Meanwhile, the Fmoc amino acid (3.5 equiv) was added to a 68 mM soln of bis(trichloromethyl) carbonate in dry THF [1.15 mM of bis(trichloromethyl) carbonate]. 2,4,6-Collidine (10 equiv) was added to the clear soln, upon which a precipitate of collidinium chloride formed. DIPEA (8 equiv) was added to the resin, immediately followed by addition of the suspension. The mixture was shaken for the times given in Scheme 39, filtered, and washed. 

Shortly after World War II, a research chemist at the Standard Oil Development Company (Esso) strolled into an oil additive laboratory and saw an interesting intermediate called perchloro-methyl mercaptan (CCI3SCI). A. F. Kittleson, spurred by visions of the trichloromethyl group in that then new miracle drug DDT, decided to try some reactions with the above described sulfenyl halide. 

However, reaction of acyclic dienamines with hydrazoic acid gives a mixture of products derived by 1,2-, 1,4- and 3,4 + 1,2-addition of HN3 to the diene system. In this case C-protonation is followed immediately by addition of the strongly nucleophilic azide anion, so that equilibrium of the C-protonated enamines cannot occur3c. Treatment of the morpholine dienamine of isophorone with trichloroacetic acid in boiling benzene resulted in decarboxylation and the 1,4-addition of a proton and the trichloromethyl anion. Basic hydrolysis of the adduct gave dienoic acid 54 (Scheme 4). 

Trichloromethyl ChloroformateA 100 ml. of methyl formate are placed in a flask connected by a ground-glass joint with a condenser containing ice and salt. From the commencement the flask is exposed to a 500-watt lamp, and the current of chlorine then started and maintained at a very low speed in the early phase, so that the temperature is maintained at 30° C. As the reaction proceeds the rate of addition of the chlorine is gradually increased, so that the temperature finally reaches about 90° C. The chlorination is complete after about 30 hours. 

It is seen from Table 81 that exo-norboraneformyl peroxide undergoes decomposition about 7 times faster than the corresponding CKi/o-peroxide. The difference in rate was attributed to steric effects . In contrast, the rates of decomposition of the corresponding exo- and emfo-norbornene peroxides (Table 81) were quite similar. Furthermore, the unsaturated peroxides were extremely sensitive to induced decomposition while the saturated peroxides were not. It was suggested from an evaluation of the kinetic data along with product studies, that the unsaturated peroxides underwent decomposition by initial addition of a trichloromethyl radical... 

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