Tolylsulfonyl azide

Triflones reacted with p-tolylsulfonyl azide in the presence of two equivalents of base (NaH/glyme) and afforded vinyl azides380. These azides were reduced with LiAlH4 to afford the corresponding amines and, upon treatment with triethyl phosphite, they gave ketones after hydrolysis381. 

Similarly, 2-formyl cyclohexanone (79), 4-formyl seven membered heterocyclic ketones (81), and 5-formylbenzfuranone (83) are converted to the corresponding diazo ketones 80, 82, and 84 usingp-tolylsulfonyl azide and p-benzoic acid sulfonylazide.43,30... 

A three-component reaction for the synthesis of functionalized benzimidazoles from terminal alkynes, o-aminoanilines, and / -tolylsulfonyl azide is developed by Wang and coworkers (Scheme 8.52). The C(sp)-H bond of alkyne was activated in this reaction via Cul-catalyzed azide-alkyne cycloaddtion (CuAAC) reaction which could lead to the formation of a ketenimine intermediate by the release of N2- The benzimidazoles could be obtained by intramolecular nucleophilic addition and subsequent elimination of amide intermediate with 2% H2SO4 under reflux conditions [91]. They also developed another protocol for the synthesis of substituted benzimidazole derivatives via a sequential three-component cascade reaction from sulfonyl azides, alkynes, and 2-bromoanilines using Cul as catalyst. Similarly, the C-H bond of alkyne was activated at the process of copper-catalyzed azide-alkyne cycloaddtion (CuAAC) reaction [92]. 

The addition of the pseudohalogen iodine azide (prepared from iodine monochloride and sodium azide in acetonitrile) to methyl 5,6-dideoxy-2,3-di-0-p-tolylsulfonyl-a -L-arabtno-hex-5-enofuranoside has also been achieved a crystalline /3-iodo azide was isolated, in 69% yield, that was stable in the dark, but became colored on exposure to light.130 Brimacombe and coworkers133 have reported the addition of iodine azide to 5,6-dideoxy-l,2-0-isopropylidene-o -D-xy/o-hex-5-enofuranose X-ray crystallographic analysis established that the product is 6-azido-5,6-dideoxy-5-iodo-l,2-0-isopropylidene-/3-L-idofuranose. 

Piperidines are obtained from 5-amino-5-deoxy sugars by cycliza-tion with C-l their preparation therefore follows the general methods of preparation of such amino sugars. The 5-O-p-tolylsulfonyl- or 5-0-(methylsulfonyl)-pentoses constitute excellent starting-materials, as these sulfonyloxy groups can be replaced by azide, and the azides can be reduced to the 5-amino derivatives, which are capable of cyclization.240-251 The formation of piperidine 178 from 5-O-p-tolyI-sulfonyl-L-arabinose diethyl dithioacetal240 (176) and 177, and of 181 from benzyl 2,3-0-isopropylidene-5-0-(methylsulfonyl)-a-D-lyxofuranoside250 (179) and 180, are examples of this reaction sequence. 

Nucleophilic displacement of the sulfonate groups in methyl 2,6,2, 3, 4 -penta-0-acetyl-3,6 -di-0-(methylsulfonyl)-/3-maltoside was readily achieved with sodium azide in hexamethylphosphoric triamide, to give methyl 3-azido-4-0-(6-azido-6-deoxy-a-D-gluco-pyranosyl)-3-deoxy-/3-D-allopyranoside pentaacetate.45 Catalytic hydrogenation of the 3,6 -diazide, followed by acetylation, gave the 3,6 -diacetamido derivative in high, overall yield. In a similar sequence of reactions, methyl 2,3,2, 3, 4 -penta-0-acetyl-6,6 -di-0-p-tolylsulfonyl-/3-maltoside has been transformed into the corresponding 6,6 -diac-etamido derivative.45... 

A corresponding equilibrium between the pyrrolidine form, the Schiff base, and the dimer exists in aqueous solutions of 4-amino-4,5-dideoxy-L-xylose. Its synthesis proceeds from D-arabinose to 5-O-p-tolylsulfonyl-D-arabinose diediyl dithioacetal, which is reduced to 5-deoxy-D-arabinose diethyl dithioacetal. This compound, in the form of its 2,3-0-isopropylidene acetal, is transformed into 5-deoxy-2,3-O-isopropylidene-D-arabinose diethyl acetal. p-Toluenesulfonyl-ation followed by treatment with sodium azide gives 4-azido-4,5-dideoxy-2,3-0-isopropylidene-L-xylose diethyl acetal, which is reduced in the presence of Raney nickel catalyst to 4-amino-4,5-dideoxy-2,3-0-isopropylidene-L-xylose diethyl acetal (104). 

The tautomeric relationships have been investigated for all four of the 5-acetamido-5-deoxypentoses. 5-Acetamido-5-deoxy-l,2-0-iso-propylidene-a-D-xylofuranose (161) is obtainable by reaction of 1,2-O-isopropylidene-5-O-p-tolylsulfonyl-a-D-xylofuranose with ammonia or sodium azide, followed by acetylation of the amino compound. The preparation of larger amounts is more suitably... 

Derivatives of 4-acetamido-4-deoxy-D-ribose have been extensively investigated. Methyl 2-0-benzoyl-3,4-di-0-p-tolylsulfonyl-j8-L-ara-binopyranoside reacts with sodium azide to give, by selective replacement on C-4, methyl 4-azido-2-0-benzoyl-4-deoxy-3-0-p-tolylsuIfo-nyl-a-D-xylopyranoside. Methyl 4-acetamido-2-0-benzoyl-4-deoxy-... 

The p-tolylsulfonyl epoxide 111, readily available (see Sect. V,l) from levoglucosan (6), reacts with a series of reagents, such as alcohols, ammonia, azides, halides, hydrogen, and thiols, to give the 4-substituted derivatives of l,6-anhydro-2-0-p-tolylsulfonyl-/3-D-gluco-pyranose (139), where X is H,742 734 OH,504 MeO,499 505 Me2CHO,496... 

Another example of a cis-fused, five-membered ring-system occurs in 3,6-anhydrohexofuranose derivatives, and 3,6-anhydro-l,2-0-isopropylidene-5-O-p-tolylsulfonyl-a-D-glucofuranose (27) contains an endo-sulfonyloxy group which can readily be displaced by sodium azide in N,N-dimethylformamide, and by hydrazine314 or sodium benzoate in 2V,2V-dimethylformamide,315 to give L-idose derivatives. 

The 5-sulfonyloxy group of methyl 2,3,5-tri-0-p-tolylsulfonyl-/3-D-ribofuranoside (73) can be selectively displaced by sodium azide in N,N-dimethylfonnamide at 120° (30 minutes).282 Treatment of the monoazide (or of 73) with the same reagents at 145° for 2 hours gave... 

The preparation of monosubstituted cycloamyloses has also been achieved, and depends primarily on the isolation of 6-O-p-tolylsulfonyl-cyclohexaamylose from the products of short-term p-toluenesulfonylation of cyclohexaamylose. By appropriate, nucleophilic displacements, this compound may be converted into the 6-azido-6-deoxy, 6-bromo-6-deoxy, 6-chloro-6-deoxy, and 6-deoxy-6-iodo derivatives reduction of the azide and iodide gives 6-amino-6-deoxy- and 6-deoxy-cyclohexaamylose, respectively. The preparation of monoesters, namely, cyclohexaamylose monobenzoate, cyclohexaamylose 2,5-pyridinedicarboxylate, and... 

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