Tosylates bromination

Rotane was first synthesized by Rippol and Conia29. The key steps included the synthesis of dispirononanone 13 (equation 11). Condensation of 13 with formaldehyde provided the tetrahydroxymethyl derivative 32, which was converted into the tetraspiro compound 33 by tosylation-bromination followed by reductive cyclization. Subsequent Wittig methylenation and cyclopropanation of the ketone 33 completed the synthesis (equation 30). 

Mesylated and Tosylated Celluloses. It has been estabUshed that the flame resistance of ceUulose (qv) is improved by oxidation of —CH2OH groups to —COOH (58—60). To correct some of the shortcomings of this treatment, mesyl or tosyl ceUulose was prepared and then the mesyl (CH2SO2) or tosyl (CH2CgH4S02) group was replaced with bromine or iodine (58—60) ... 

By similar procedures diazirines were prepared not only from simple aliphatic ketones but also from hydroxyketones and )3-aminoketones (B-67MI50800), and so were a large number of diazirines from steroidal ketones (65JA2665). Permanganate, bromine, chlorine and hypochlorite were used as oxidants. A one-step preparation of diazirines from ketones like 3-nonanone, ammonia and chlorine has been claimed in a patent (66USP3290289). 3,3-Diazirinedicarboxylic acid derivatives like (286) were obtained directly from oxime tosylates by the action of two moles of O-ethoxyamine (81AG(E)200). 

Similarly, replacement of the bromine in 19-bromo-3 -acetoxyandrost-5-ene (199) proceeds smoothly to yield 19-djL-androst-5-en-3jS-ol (200) while attempts to displace the corresponding tosylate or mesylate give unsatisfactory results. ... 

Azaloxan (12) is an antidepressant agent. Its synthesis can be accomplished starting with the reaction of catechol (7) and 3,4-dibromobutyronitrile (obtained by addition of bromine to the olefin) to give l,4-benzodioxan-2-ylacetonitrile (8). A series of functional group transformations ensues [hydrolysis to the acid (9), reduction to the alcohol (10) and conversion to a tosylate (11)] culminating in an SN-2 displacement reaction on tosylate 11 with l-(4-piperidinyl)-2-imidazolidi-none to give azaloxan (12) [3]. 

Amino-77/-dibenz[/),t/]azepin-7-ones, e.g. 7, prepared either by successive bromination, aminodebromination, and dehydrogenation of 5-tosyl-5A/-dihydro 7>,t/]azepin-7(6//)-ones, or by the oxidation of 6-ethoxy-6,7-dihydro-5//-dibenz 7>,r/]azepincs with lead(IV) acetate followed by aminodemethoxylation, on treatment with a bidentate nucleophile (e.g.. benzene-1,2-diamine or 2-aminobenzenethiol) yield the pentacyclic systems 8 and 9, respectively.27... 

In a similar manner, bromination, dehydrobromination and amination of l-tosyl-l//-l-benz-azepin-3(2/7)-one yields the 2-amino-3//-l-benzazepin-3-one 10, which condenses with ben-zene-1,2-diamine to give 6//-l-benzazepino[2,3-6]quinoxaline (11).27... 

Recendy, Guiver et al. reported a number of derivatives of polysulfone and poly(aryl sulfone).172 188 Polysulfones were activated either on the ortho-sulfone sites or the ortho-ether sites by direct lithiation or bromination-lithiation. The lithiated intermediates were claimed to be quantitatively converted to azides by treatment with tosyl azides. Azides are thermally and photochemically labile groups capable of being transformed readily into a number of other useful derivatives. 

In the hydrolysis of the tosylate (21a) the predominance of exo isomers (21b) relative to endo isomers indicated the importance of steric hindrance of the C( 1) Me group to endo attack by the nucleophile. An analogous result was found for the products of bromination (21d) of the corresponding iodides (21c). 

The triazide (23) has been synthesized from the bromination of the tosylate (22) followed by displacement of both bromide and tosylate functionality with sodium azide. ... 

Other papers of interest in this section report transamination of camphor-3-carbothioamides with secondary cyclic amines, reaction of camphorquinone with dimethyl /S-ketoglutarate, the use of fenchone (212 X=0) in alkene formation from Grignard reagents, bromination of 2-e/itfo-6-endo-dibromobornane to yield 2,3,6-endo-tribromoborn-2-ene, and camphor-enol trimethylsilyl ether formation by quenching the reaction mixture of butyl-lithium and camphor tosyl-hydrazone with trimethylsilyl chloride. ... 

Selective tosylation introduces leaving groups in the a and oo positions in the aldonolactones, the same positions which were substituted with bromine if the lactones were treated with HBr-HOAc. In the latter case, bromine was introduced with inversion of the configuration at C-2, whereas the tosylation does of course not alter the configuration at this center. Thus, the two methods give activated aldonolactones with different stereochemistry at C-2 (Scheme 1, entries I and IV). 

The l,3,3,3a,8a-tetrahydro-8-oxa-2-thia- 205, l,3,3,3a,8a-tetrahydro-2,8-dioxa- 206, and 3,3a,8,8a-tetrahydro-12/-2-thia-8-aza-cyclopenta[ ]indene-2,2-dioxide 207 were prepared by Michael addition or radical cyclization from the corresponding sulfones 202-204 and brominated-dehydrobrominated (in the case of 207, after tosylation) to produce 1,5-diheteropentalene systems 208-210, respectively <1997TL5315>. 

In view of this apparent resistance of triazolium to bromination with electrophilic bromine, it is interesting to discover that 1,3-dimethyl-1,2,3-triazolium tosylate (71) was 4-brominated by bromine and NBS. When the 4-bromo salt (72) is dissolved in base, an equilibrium is established containing unbrominated salt (71) and 4,5-dibromo salt (73). Presumably, base converts 72 into an ylid, which is further brominated by 72. A similar product mixture was obtained from the isomeric 5-bromo tosylate (74) [69ACS(B)2733 71ACS(B)249] (Scheme 27). 

In an interesting fragmentation reaction, the hexahydroazocine (23) is formed by solvolysis of (22) in the presence of NaBHt in 94% yield (75TL2613). A related compound (24) can be prepared from 4-cycloheptenone oxime tosylate via the unsaturated lactam (25) (79JOC287). Whereas (25) adds bromine to the double bond, (24) undergoes a transannular reaction to give a 1-substituted pyrrolizidine (26). The latter type of reaction also occurs... 

In the copper catalyzed aromatic nucleophilic substitution of aryl halides bromoindole derivatives were converted to the appropriate cyanoindoles. Both 5-bromoindole and its 7V-tosyl derivative gave excellent yields, when a substoichiometric amount potassium iodide was added to the reaction mixture (6.80.), Pyrazole and benzothiophene showed a similar reactivity. The role of the added iodide is to activate the aromatic system through a bromine-iodine exchange.111... 

The evident interest attending this method of bromination was reinforced by the observation that the reaction may be conducted in the presence of a wide range of other groups that are unaffected under these conditions (for instance, O-mesyl, -tosyl, -acetyl, -benzoyl, and -methyl groups, and a-epoxides).116... 

Similar oxidation of alcohols has been carried out with dimethyl sulfoxide and other reagents317 in place of DCC acetic anhydride,318 SOy-pyridine-triethylamine,319 trifluo-roacetic anhydride,320 oxalyl chloride,321 tosyl chloride,322 chlorine,323 bromine,324 AgBF4-Et3N,325 P205-Et3N,326 phenyl dichlorophosphate,327 trichloromethyl chloroformate,328 tri-... 

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