Sulfonyl halides coupling

In the early solution phase syntheses of oligonucleotides, coupling of phosphate diesters was used. A mixed 3 -ester with one aryl substituent, usually o-chlorophenyl, was coupled with a deprotected 5 -OH nucleotide. The coupling reagents were sulfonyl halides, particularly 2,4,6-tri-i-propylbenzenesulfonyl chloride,53 and the reactions proceeded by formation of reactive sulfonate esters. Coupling conditions... 

Other reactions have been studied for synthesizing these polymers, including the electrophilic aromatic substitution of acyl and sulfonyl halides on aromatic reactants and the nickel-catalyzed aromatic coupling of aromatic dihalides [Yonezawa et al., 2000]. 

The only unusual coupling constant associated with the sulfonyl halides is that observed between the sulfonyl fluoride group and the adjacent-aliphatic group... 

Scheme 6 Carbonylative Stille cross-coupling of vinyl halides, triflates, and sulfonyl chlorides.

As another alternative to triflates, aryl nonaflates (ONf) are easily prepared from phenol and commerically available perfluorobutane sulfonyl fluoride 243, and used for Pd-catalysed coupling with halides [111]. Aryl nonaflates are more reactive than aryl triflates. / -Iodophcnyl nonaflate (244) gives 245 by chemoselective reaction of the... 

Reactive halide (5) bearing electron-withdrawing groups, such as ester, cyano, or sulfonyl groups, at the a-position react with Fe/CuBr to form a, 3-diester (6) in good yield, through the coupling of the a-ester radical formed via SET as shown in eq. 2.3 [7]. 

Ladlow and coworkers have reported the use of fluorous-tagged aldehydes as a protecting group in the synthesis of a library of sulfonamides. The F-aldehyde was prepared via a simple alkylation of 4-hydroxy-2-meoxybanzaldehyde with a perfluo-roalkyl halide. The authors have protected various primary amines with the F-aldehyde followed by reduction, sulfonylation and Suzuki coupling and acid-mediated deprotection. Filtration via a fluorous SPE (solid phase extraction) was... 

Sulfonyl chlorides are totally defunctionalized (with loss of SO2 also) during coupling with Grignard reagents. Alkenylmagnesium bromides and alkyl halides (bromides and iodides) are coupled in the presence of FeCls and TMEDA, whereas for the formation of ArMgBr and RX a complex derived from FeCls and 1 has been identified. ... 

In l-hthio vinyl sulfides (sec. 8.6) the sulfur atom stabilized the carbanion, allowing either alkylation or condensation reactions. The sulfonyl moiety can also stabilize a vinyllithium derivative. Vinyl sulfone (321), for example, was converted to the 1-lithio derivative with methyllithium.332 xhis organometallic reacted in the usual manner with alkyl halides (methyl iodide) to give the coupling product, 322. 

Various synthetic approaches have been demonstrated for the synthesis of PAEs since early days [35 0], PAEs were synthesized by Ullmann condensation between bisphenols and aryl fcis-halide monomers using Cu(I) salt/pyridine as catalyst [36], General Electric developed the first commercially successful PAE poly(2,6-dimethyl phenylene oxide) (PPO) [38], It was prepared by oxidative coupling of 2,6-dimethyI phenol. However, this process has its own restrictions, because it does not allow much structural variation or inclusion of any electron-withdrawing group into the polymer main chain. First attempts to synthesize polysulfones (PSF) were successfully done by Friedel-Crafts sulfonylation reaction of arylenedisulfonyl chlorides, for example, diphenyl ether-4,4 -disulfonyl chloride with diaryl ethers, for example, diphenyl ether, or by self-condensation of 4-phenoxy benzene sulfonyl chloride in the presence of FeCls [41], Whereas the former reaction involves side reactions (sulfonylation not only in the para- but also in the ort/io-position), the latter produces only the desired linear all-para products. 

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