Alkylation with tosylates

Benzene-fused sulfolenes were found to be readily alkylated with alkenyl side-chains and the alkylated products, when heated, were converted to o-quinodimethanes by SO2 extrusion. These spontaneously reacted in an intramolecular Diels-Alder fashion, to produce tricyclic systems with good stereochemical control. The methodology was exploited in a short and efficient synthesis of ( )-estra-l,3,5(10)-triene-17-one (228) [89] (Scheme 6.71). Sulfolene (223) was first alkylated with tosylate (224) to provide (225) in good yield. After ketal removal, (226) was thermolysed to provide estratriene (228) in 85% yield, via o-quinodimethane (227). The compound was contEuninated by 5-7% of the C-9 epimer, which was easily removed by recrystallization. 

G>Alkylation with tosylates Gycloalkanedicarboxylic acid esters from ditosylates... 

Di(trifluoroethoxy)phthalodinitrile 122 can be prepared from 2,3-dicyanohydroquinone 121 by alkylation with trifluoroethyltosylate in DMF [70], The 4,5-substituted dinitrile 125 is available from the 4,5-dibromocatechol 123 by consecutive alkylation with tosylate (DMF, K2CO3) and cyanation (CuCN, DMF) [70], 0=Ti" complexes of a- and p-octakis(trifluoroethoxy)phthalocyanines were prepared using these dinitriles 122 and 125 [70]. The Zn" complex of p-octasubstituted phthalocyanine was also reported [78],... 

Regiospecific syntheses with allylmagnesium halides y-Alkylation with tosylates... 

Alkylation with tosyl- and trifluoracetamides has also been reported but their harsh deprotection conditions prevent their suitabihty for solid phase chemistry of polyamines [254-256]. 

Alkyl sulfates, tosylates, and other esters of sulfuric and sulfonic acids can be converted to alkyl halides with any of the four halide ions. Neopentyl tosylate... 

Neutral tertiary and secondary amides react with very reactive alkylating agents, such as triethyloxonium tetrafluoroborate, to give O-alkylation.63 The same reaction occurs, but more slowly, with tosylates and dimethyl sulfate. Neutralization of the resulting salt provides iminoethers. 

Secondary amines, such as pyrrolidine, must be alkylated with care too polar a solvent leads to participation of a second nearby polymer-bound alkylant in the formation of a quaternary ammonium salt, along with the desired immobilized trialkyl amine. The exception, as seen above, is diisopropylamine, which refuses to displace tosylate even in the refluxing pure amine, or in hot dimethyl-formamide or other polar solvent, while metal diisopropylamide is notorious as a powerful non-nucleophilic base. However, carboxamide is not difficult to form from (carboxymethyl)polystyrene, again using toluenesulfonyl chloride as condensing agent this can then be reduced to (diisopropyl-ethylaminoethyl)polystyrene, which is of interest as a polymer-bound non-nucleophilic base. ... 

Z,9S,10 )-9,10-Epoxyhenicos-6-ene (13) is the female sex pheromone of moths such as ruby tiger moth (Phragmatobiafuliginosa), fruit-piercing moth (Oraesia excavata), and painted apple moth (Teia anartoides). Scheme 23 summarizes Shi s synthesis of 13 based on Sharpless asymmetric dihydroxylation (AD) [36]. Mori synthesized 13 employing lipase to prepare A (Scheme 24) [37]. Alkylation of the acetylide anion C was possible neither with tosylate nor with iodide, but triflate B could alkylate C to give D. 

This route involves the conversion of a 3,4-diiodopyrrole (139) to the corresponding 3,4-diboronate ester (140) followed by a bis Suzuki cross-coupling reaction with a bromoquinoline, which generates the halitulin core (141). This pyrrole (141) is then alkylated with a tosylated cycloazadecane to generate a pentasubstituted pyrrole (143), which is converted to halitulin by debenzylation under hydrogenolysis conditions. 

Sulphonic esters have been obtained from the sulphonyl chlorides in high yields under mild conditions for a range of alcohols and phenols [e.g. 18, 19]. Of particular value is the protection of glycosides possessing a free hydroxyl group and hydroxy-steroids, which are tosylated readily under phase-transfer conditions [20-22]. Alkyl sulphinites have been obtained in a similar manner [23]. Alternatively, preformed tetra-rt-butylammonium sulphonates or their alkali metal salts have also been alkylated with haloalkanes or alkyl fluorosulphonates [24,25]. In contrast with more classical procedures, tosylation of alcohols, which are susceptible to E/Z-isomerism, e.g. Z-alk-2-en-l-ols, occurs with retention of their stereochemistry under phase-transfer catalysis [26]. 

Arylamines and hydrazines react with tosyl azide under basic conditions to yield aryl azides [1] and arenes [2], respectively, by an aza-transfer process (Scheme 5.25). Traditionally, the reaction of anilines with tosyl azides requires strong bases, such as alkyl lithiums, but acceptable yields (>50%) have been obtained under liquidiliquid phase-transfer catalytic conditions. Not surprisingly, the best yields are obtained when the aryl ring is substituted by an electron-withdrawing substituent, and the yields for the corresponding reaction with aliphatic amines are generally poor (-20%). Comparison of the catalytic effect of various quaternary ammonium salts showed that tetra-/i-butylammonium bromide produces the best conversion, but differences between the various catalysts were minimal [ 1 ]. 

Alkyl azides are conveniently prepared from the reaction of alkali metal azides with an alkyl halide, tosylate, mesylate, nitrate ester or any other alkyl derivative containing a good leaving group. Reactions usually work well for primary and secondary alkyl substrates and are best conducted in polar aprotic solvents like DMF and DMSO. The synthesis and chemistry of azido compounds is the subject of a functional group series. ... 

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