With tert.-Butyl Hypochlorite

When stirred for a few minutes with equimolar amounts of terr.-butyl hypochlorite in methanol/dichloromethane at 0° and then with aqueous sodium hydrogen carbonate solutions, diorgano tellurium compounds were converted in good yields to diorgano tellurium oxides The /ert.-butanol formed during hydrolysis is easily removed under reduced pressure. 

Dihexadecyl Tellurium Oxide Hydrate 0.50 g (0.87 mmol) of hexadecyl teliurium is dissoived in 20 ml of methanol/dichloromethane (1/1, v/v), the solution is cooled to 0°, 0.11 g (1.0 mmol) of ttrt.-butyl hypochlorite are added, and the mixture is stirred for 1 min. The mixture is diluted with 20 ml of dichloromethane, 20 ml of saturated aqueous sodium hydrogen carbonate solution are added, and the mixture is stirred for 5 min. The organic phase is separated, dried with anhydrous sodium sulfate, the solvent is evaporated, and the residue is recrystallized from hexane/ethanol (1/1, v/v) yield 0.49 g (96%) m.p. 92-95°. 

---

If a bromomethyl- or vinyl-substituted cyclopropane carbon atom bears a hydroxy group, the homoallyiic rearrangement leads preferentially to cyclobutanone derivatives (J. Sa-laun, 1974). Addition of amines to cydopropanone (N. J. Turro, 1966) yields S-lactams after successive treatment with tert-butyl hypochlorite and silver(I) salts (H.H. Wasserman, 1975). For intramolecular cyclopropane formation see section 1.16. 

A) The preparation of [H-chloroethoxyjchloromethyl]phosphonic acid Acetaldehyde (1.1 mol) and hydroxymethylphosphonlc acid (1 mol) in 500 ml of benzene are saturated with hydrogen chloride gas at 10°C to 15°C. The mixture is aged at 25°C for 24 hr, the solvent distilled out in vacuo and the residue flushed three times with benzene to remove all traces of hydrogen chloride. The residue is taken up in benzene (500 ml), treated with tert-butyl hypochlorite (0.8 mol) and azobisisobutyronitrile (0.8 mm) at 40°C until titration shows the absence of hypochlorite and the solution is then evaporated to yield [(1-chloro-ethoxy)chloromethyll phosphonic acid in the form of an oil. 

Acridine-9-carbaldehyde (24%) is one of several products formed from the oxidation of 5//-dibenz[A/]azepine with tert-butyl hypochlorite in dichloromethane at — 70 C.229 The reaction is even more complex in the presence of silver(I) trifluoroacetate, and an analysis of the reaction mixture by GC-MS techniques reveals the presence of eleven products, the major ones being acridine (37%), an unidentified 5//-dibenz[/ ,/]azepinecarbaldehyde (23%) and acridine-9-carbaldehyde (9 %). 

The chromatogram is freed from mobile phase in the drying cupboard (10 min 160 °C) and placed while still hot in the chamber with tert-butyl hypochlorite vapor for 5 min. After removal of excess reagent (15 min stream of warm air) the chromatogram is sprayed with reagent 2. 

Chlorination of yohimbine (74) at the (3 position of the indole moiety with tert-butyl hypochlorite and treatment of the resulting chloride (539) with base in... 

In certain cases, where the reaction with tert-butyl hypochlorite is tardy, reaction in the light with the addition of a trace of molecular bromine has been used °. ... 

The most widely used, and often most convenient reagents for such one-pot reactions are sodium hypochlorite (45) or hypobromite (16). These reactions are performed in the presence of an organic base (generally triethylamine) that normally enhances the yield of cycloaddition products (45). This method was employed for many intermolecular reactions (71) and also seems especially suited for intramolecular ones (72-77) as well as for the solid-phase synthesis (78) of 2-isoxazolines. Hypohalite can also be replaced by sodium broruite in combination with a catalytic amount of tri-u-butyltin chloride (79). In a related method, O-tributylstannyl oximes were treated with tert-butyl hypochlorite to produce nitrile oxides that were trapped with aUcenes or alkynes to afford the corresponding isoxazolines or isoxazoles in moderate to good yield (80). 

The final, critical oxidative spirocyclization of the 2,3-disubstituted indole to the spiro oxindole was effected by treatment of 124 with tert-butyl hypochlorite in pyridine to provide the labile 125 [Fig. (34)]. The Pinacol-type rearrangement was conducted by treating compound 125 with p-toluenesulfonic acid in THF/water. It is assumed that the chlorination of 124 proceeds from the least hindered face of the indole, to give the a-chloroindolene 125. The hydration of the imine functionality must also occur from the same a-face that is syn to the relatively large chlorine atom furnishing the syn-chlorohydrin 126, that subsequently rearranges stereospecifically to the desired spiro oxindole 127. 

Partially proton-exchanged Na faujasite X, in turn, is the best catalyst for selective monochlorination with tert-butyl hypochlorite.258 NaX, NaY, and NaKL zeolites used in the chlorination of toluene with sulfuryl chloride undergo rapid deactivation because of the accumulation of polychlorinated toluenes in the pores of the catalysts and dealumination.259, 260 Direct electrophilic fluorination of aromatics can be effected by using Selectfluor in the presence of triflic acid.261 Electrophilic fluorination may also be carried out by R2NF and R3N+FA reagents.262 Elemental fluorine may also act as a powerful electrophile in acidic media (sulfuric acid, trifluoroacetic acid, or formic acid), but monosubstituted aromatics give isomeric mixtures.263-265... 

The method of N-chlorination of amino acid esters 40 and AT-acylamino acid esters with tert-butyl hypochlorite and subsequent elimination of hydrogen chloride is of general use in the preparation of DHA derivatives 41/42 122-1241 (Scheme 15). 

The C = C bond in 3,3,3-trifluoro-2-methylprop-l-eneis readily oxidized in 76 % yield by bubbling the substrate into a cooled solution of hypochlorous acid (Table 6).98 Chlorohydrins together with 1,2-dichloro derivatives arc obtained by oxidation of alkenes with tert-butyl hypochlorite when the reaction is performed in acetic acid instead of water, chlorohydrin acetate is formed (Table 6)."... 

Hexamethyldisilane is converted to (chloromethyl-) and (dichloro-methyl)pentamethyldisilane in lower yield by treatment with tert-butyl hypochlorite under ultraviolet irradiation (166). This process is accompanied by the significant formation of products arising from cleavage of the silicon-silicon bond and subsequent reactions. 

Oxidation of 4-methoxyphenyl dodecyl tellurium with tert- butyl hypochlorite in benzene gave a 1 2 1 mixture of the diorgano tellurium, its oxide, and its dioxide3. 

Compared with chlorination, hydrogen abstraction reactions of alkoxy radicals are relatively insensitive to solvent effects [160, 222, 223]. The results of the AIBN-initiated radical chain chlorination of 2,3-dimethylbutane with tert-butyl hypochlorite indicate a solvent effect on tert-butoxy radical reactions of much smaller magnitude, but greater selectivity in aromatic solvents [222, 223], The reduced solvent effect for this hydrogen abstraction reaction has been attributed to steric effects. Due to the bulky... 

Homer-Wittig reagent had to be developed. In the first version of the synthesis (11,90) the olefination was carried out with a reagent derived from simple semicarbazide. It was found later (91), however, that the fully methyl-protected reagent gave much better yields. The trimethylsemicarbazone 65 was isolated in 55% yield and appeared to be the pure anti compound ( H NMR 8 7.52, d, 8-H). On treatment with tert-butyl hypochlorite followed by addition of triethylamine, 65 yielded a 7 3 mixture of the 4(7) and 4(7)Z stereoisomers of the corresponding betalamic acid derivative 66, which on recrystallization afforded the pure 4(7) compound. 

Finally, ( )-2-chloro-8a-cyano-dccahydro-2-nitrosonaphthalcnc (7), readily obtained by treating rra .s-8a-cyano-octahydro-2(l//)-naphthalenone with tert-butyl hypochlorite, undergoes hetcro-cycloaddition with 1,4-disubstituted dienes leading stereoselectively to a single product 8 in good yield40. 

Carbohydrates have a wide range of structural variations and these can be used to evaluate steric and stereoelectronic effects. This feature has been utilized in hetero-Diels-Alder cycloadditions. Thus, 2,3 5,6-di-0-isopropylidene-D-mannonolactone oxime, on reaction with tert-butyl hypochlorite, gives the corresponding 1-chloro-l-nitroso derivative 1 which is stable at 20°C for several days the configuration was assigned by X-ray analysis92-93. 

The same 8-chloroadenosine (5) is also obtained with tetrabutylammonium iodotetrachloride (TBAIClJ or with tert-butyl hypochlorite (r-BuOCl) in dimethylformamide. Analogous chlorination of -methyladenosine, to give 6, and A. A -dimethyladenosine is also possible with the latter reagent. ... 

Effectively, they undergo ring expansion into cyclobutanones with a variety of electrophilic reagents with hydrobromic, perbenzoic acids and with tert-butyl hypochlorite, 2-alkyl-, 2-hydroxymethyl- and 2-chloroalkylcyclobutanones are obtained, respectively . The rearrangement takes place most probably through an intermediate cyclopropylcarbinyl cation (equation 77). 

When diaryl telluriums were oxidized with tert.-butyl hypochlorite and the oxidation products reacted with sodium sulfonamides, diaryl tellurium sulfonimides were obtained in quantitative yield, ... 

Carboline-3-carboxylates (574) were prepared through the dehydrogenation of l,2,3.4-tetrahydro-/ carboline-3-carboxylates (573) with tert-butyl hypochlorite in the presence of a tetriary amine (e.g., DBU) in an inert solvent (86GEP 3504045). 

Both tert-butyl hypochlorite and N-chlorosuccinimide dehydrogenate primary benzylic alcohols to the aldehydes (equation 213), whereas primary aliphatic alcohols are converted into esters of the corresponding acids [709]. Butyl alcohol dissolved in carbon tetrachloride and treated with tert-butyl hypochlorite in the presence of pyridine at 40-45 C gives, after 2 h, a 66% yield of butyl butyrate [709]. 

Methyl urazol 225 is oxidized into iV-methyl triazoline-3,5-dione with tert-butyl hypochlorite. Without isolation it reacts with ( )-penta-2,4-diene-l-ol giving adduct ( )-226 as a racemic mixture. On treatment of ( )-226 with a lipase (R/Novozym 435) in vinyl acetate 38% of ester (5)-227 (86% ee) and 29% of alcohol R)-226 (59% ee) is isolated. Epoxidation of (S)-227 provides 13% of (—)-228 and 68% of (—)-229. The latter epoxide is hydrolyzed under acidic conditions to provide 230 that reacts with hydrazine to give enantiomerically pure (—)-l-azafagomine (O Scheme 80) [394]. This compound has a slow binding inhibitor of almond /3-glucosidase Ki = 0.33 pM). A similar sequence of reactions converts (R)-226 into (+)-l-azafagomine. The latter is not an inhibitor of 8-glucosidases [395]. 

Chlorination of toluene with tert-butyl hypochlorite in the presence of silica gel gave a mixture of chlorotoluenes in which the ortho isomer predominated. Rutming this reaction using a large pore zeolite, H-X, gave p-chlorotoluene in... 

The oxidation of alcohols 44 with tert-butyl hypochlorite proceeding through the intermediacy of cr-telluranes 47 leads to the formation of diastereomeric mixtures (in case R3 / H) 1,2-oxatelluroles 42 in 44-82% yields (93ZOK1068, 94KGS266) (Scheme 27). 

Hexahydro-3//-benzoxatelluroles-2,l 72 and 73 containing tetracoordinated tellurium centers have been obtained using the methodology applied to the syntheses of 5i/-oxatelluroles-l,2 and 3i/-benzoxatelluroles-2,l. The oxidation of (A)-lO-organ-yltelluro-2-exoborneols 74 with tert-butyl hypochlorite affords 72 in 86-97% yields... 

The addition of cyclopropanone to a large variety of primary amines, including amines with a primary, secondary or tertiary alkyl substituent, afforded the corresponding labile, but isolable, hydroxyamines 24. These amines are a suitable source of the )S-lactams 25 via a synthetic procedure which involves Af-chlorination with tert-butyl hypochlorite and subsequent treatment with silver salts. ... 

Treatment of cyclopropylamines with tert-butyl hypochlorite or 7V-cyclopropylsulfonamides with aqueous sodium hypochlorite gave the corresponding A -chloro-A -cyclopropyl analogs, e.g. 1 and in the best case in quantitative yield. 

Similarly, thermal isomerization of the [7,7- H2] isotopomer gave [3,7- H2]cyclonona-l,3,6-triene, and the [5,5,9,9- H4.] isotopomer gave [5,5,9,9- H4]cyclonona-l,3,6-triene. In contrast to these thermal ring expansions, chlorination of 1,5-bishomocycloheptadiene with tert-butyl hypochlorite yielded unrearranged, bridgehead chlorides, Silver(I) trifluoroacetate cleaved only one cyclopropane unit, without ring expansion, to afford 4-(methoxymethyl)bi-cyclo[5.1,0]octa-2,4-diene. ... 

Furukawa et al. have reported one of the most convenient methods to prepare various Martin s type sulfuranes as shown in Scheme 25 [61]. Thianthrene S-monoxide (33) was found to react with alkyl Grignard reagents affording the o,o -bis-Grignard reagent of diphenyl sulfide, which was converted initially into the corresponding diols 34 on treatment with aldehydes or ketones, and then to the Martin s sulfuranes 35 by treatment with tert-butyl hypochlorite. 

---