From tosylates

Mesylates and tosylates may be used as variants of the 0-sulfate ester. For instance, 55% of aziridine 7 was obtained from base-mediated cyclization of amino mesylate 6. In comparison, the classic Wenker protocol only gave 3% of 7. In another instance, A-tosyl amino alcohol 8 was tosylated to give 9, which was transformed to aziridine 10 in 64% yield, along with 29% of the P-elimination product due to the presence of the ester moiety. Likewise, aziridine 12 was assembled from tosylate 11 in two steps and 60% yield. ... 

Eight grams of the crude ester, which had been prepared from tosyl azide and sodium butoxide, then stored for four weeks at 0°C, was to be distilled at 0.2 mm Hg. On the bath reaching 70°C, there was a violent explosion. This was attributed to a toluenesulphonic acid autocatalysed elimination. However, presence of butyl azide as an impurity seems probable. 

Free-radical chain reactions have been reviewed60. The cyclization of dienes by the action of free radicals is illustrated for the case of the 1,6-heptadiene derivative 90 (E = CC Me) in equation 56. Treatment with tosyl radicals, produced from tosyl chloride and a catalytic amount of dibenzoyl peroxide, generates the radicals 91, which cyclize to 92. The latter reacts with tosyl chloride to form 93 and tosyl radicals are regenerated. The product is obtained in 85% yield as a 6 1 mixture of cis- and fraws-isomers61. 

Reaction of the olefin 1065, obtained from tosylate 1023, with hydrazine gave the pyridazine 1066, whose deisopropylidenation gave 1067 (75JHC75). 

Another strategy for the synthesis of 5-deoxyhexoses involves the anti-Markovnikov hydration of a 5,6-alkene derivative, as first developed by Wolfrom.97,100 Since that report, the same approach has been followed by several authors, and conditions for the key step have been improved. For example, starting from tosylate 43, treatment with sodium iodide resulted in the alkene 44. Addition of iodine trifluoracetate (produced in situ by the reaction of silver trifluoroacetate and iodine) to 44, followed by hydrogenation over... 

Fig. 55 Direct thiolation of the dextran backbone accessible via Sn reaction starting from tosylates of dextran [368]...

Besides the direct thiolation of the polysaccharide backbone accessible via Sn reaction starting from tosylates of dextran, as discussed above, a number of paths for the introduction of spacer-bound thiol functions are described. Early attempts towards thiolation of dextran applied acetylthiosuccinic anhydride yielding the mercaptosuccinyl derivative of dextran (Fig. 56). The reaction was carried out by addition of acetylthiosuccinic anhydride to a solution of the macromolecule while the pH was maintained at 8 by addition of NaOH and subsequent treatment of the product with Amberlite [369]. 

In 2001, a modified procedure for sulfur ylide-catalyzed epoxidation, aziridination and cyclopropanation was introduced by Aggarwal and co-workers that utilized the generation of the diazo compounds in situ from tosyl hydrazone salts at 40 °C in the presence of a phase-transfer catalyst [46, 79]. (For experimental details see Chapter 14.12.1). Using this modified protocol, sulfide 4 was shown to be effective for epoxidation and aziridination (see Sections 10.2.1.4 and 10.3), but was not an effective cyclopropanation catalyst (see Table 10.3). Sulfide 28 was tried instead as it had been shown in achiral studies [96] that six-membered sulfides were more effective than five-membered analogues. This change gave rise to... 

In principle, any compound prepared by a ring-closure reaction in Section 14.11.5.3 and substituted with a removable substituent on ring nitrogen atoms can serve as a protected cycle. This is particularly true of a full range of the cyclic amides and sulfonamides (mostly tosylamides). Examples of the approach are 172 and 173 prepared by the tosylate method from tosylated and benzylated precursors <1995T1197>. Protected 16-membered tram 1,9-dibenzyl-l,5,9,13-tetraazacyclohexadecane was also obtained in this way <1998SC285>. 

Thermolysis of the cycloadducts 28 derived from tosyl isocyanate and nitrile oxides also affords N-sulfonylcarbodiimides 29. For example, N-p-toluenesulfonyl-N -2,4,6-trimethylphenylcarbodiimide, mp 71-72 °C, is obtained in 87 % yield. 

Benzoxazoles have been prepared by intramolecular reaction of a phenolic —OH groiq) with a Beckmann intermediate (equation 30). A cyclic imidate was isolated in high yield from tosylation and in situ Beckmann reaction of the erythromycin-derived oxime (4[Pg.698]

Enantiomerically pure [3]oxaferrocenophanes (405) are available as well, from tosyl chloride-induced dehydration of diols (equation 88). Tilt angles for these complexes as... 

Isopropylidene diazomalonate (1). Mol. wt. 170.13, m.p. 93-95°. This compound is prepared by diazo transfer from tosyl azide to Meldrum s acid. ... 

Sulfonyl fluorides have so far been reported to react at only two amino acid residues, cysteine and serine. The chemical evidence for the reaction of phenylmethylsulfonyl fluoride at the reactive cysteine of papain is indirect (Whitaker and Perez-Villasenor 1968). However, the strong chemical evidence for the attack of phenylmethane sulfonyl fluoride at the serine of chymotrypsin (Gold and Fahrney 1964) has been confirmed by the X-ray crystallographic structure of tosyl-chymotrypsin (Matthews et al. 1967) which had been prepared from tosyl fluoride (Sigler et al. 1966). 

Preparation from tosyl chloride and sodium azide in 83% yield. ... 

A new method for transposition of carbonyl groups starts by interception of the intermediate from tosyl hydrazone decomposition with Me3SiCl. Oxidation of the silane intermediate with MCPBA gives the transposed product. 0... 

Katritzky et al. have prepared a-amino carbanions from tosyl methyl amines. The transformation was achieved by treatment with 2 equiv of Sml2 [82] in the presence of an electrophile (Scheme 38). In the absence of HMPA the use of iso-butyraldehyde as the electrophile gave only the amine dimer (98%). However, the addition of 5% of HMPA resulted in a 67% yield of the desired product (62%) with a minor amount of diamine (17%). The formation of the hydroxy amine probably involves a carbanion intermediate whereas coupling gives the diamine. 

Table 6-1 contains some typical examples of these cycloadditions. A clever total synthesis of an unusual isonitrile fungal metabolite has been achieved using the bicyclic adduct prepared from tosyl cyanide and cyclo-pentadiene (Scheme 6-I).6... 

In the intermolecular reaction of the nitrene that is derived from tosyl azide with benzene, little of the A -tosylazepine (5) is obtained at normal pressures, but the yield is markedly increased when the reaction takes place under a high pressure of nitrogen for example, to 48% at ca 90 atm.In a similar reaction with dimethyl terephthalate, it is suggested that the reaction involves an initial [1,3] cycloaddition of the azide to the aromatic ring to give (6), rather than a nitrene reaction. 

Ethers from tosylates with simultaneous rearrangement... 

Regitz diazo transfer reactions have been reviewed previously.1-3 The following two main routes have been known for the synthesis of diazo compounds (1) diazotization of amines, oximes, nitrosoamines, and hydrazones (2) transfer of the diazo function from tosyl or mesyl azides to active methylene compounds. 

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