Arenes sulfonylation

Ruthenium complexes are capable of catalyzing halogen atom transfer reactions to olefins. This has been illustrated in the enantioselective atom transfer reactions of alkane and arene-sulfonyl chlorides and bro-motrichloromethanes to olefins using chiral ruthenium complexes. Moderate ee s up to 40% can be achieved for these transformations [74-77]. These specific reactions are believed to follow a radical redox transfer chain process. 

Polysulfones can be prepared by Friedel-Crafts sulfonylation reactions [133-150]. The carbenium ion intermediates can be generated from the Lewis acid-catalyzed reaction of involving arene sulfonyl chloride [Eq. 

The reactions of metal substituted carbodiimides 20 with arenesulfonyl chlorides or arene-sulfonyl isocyanates produce metal substituted N-sulfonylcarbodiimides 21 (R3M=Me3Si, Et3Ge, Bu3Sn X=C1, NCO). ... 

The synthesis of various azido compounds with arene sulfonyl azides has, at least in a formal sense, to be considered as an electrophilic substitution of hydrogen by an azide function.By this route a number of amines, cyclic derivatives and bridgehead compounds included, after deprotonation with NaH or Grignard reagents, could be transformed into azides in high yield on treatment with arene sulfonyl azides." Details cannot be given here. Enolates can also be converted into azido derivatives in a very similar way, via triazene intermediates. Evans et alP did recently investigate the influence of the countercation, the structure of the transfer azide and work-up conditions on this process. 

Both alkane and arene sulfonyl nitrenes insert into the carbon-hydrogen bonds of saturated hydrocarbons although not as efficiently as carbenes (10). 

Another case, in which the capture of a dipolar intermediate is reported, is the cycloaddition of an arene-sulfonyl isocyanate to a dialkyl-carbodiimide. One of the ultimate products is a 2 1 adduct, and it is suggested that an open dipolar species, the product of the first addition, adds a second molecule of isocyanate in a subsequent step. Formation of 2 1 adducts is regarded as strong evidence of cycloadditions with polar intermediates . 

Several studies have used palladium catalysis in the arylation of benzoxazoles. A palladium catalyst with a phosphine ligand allows their reaction with aryl mesylates without the requirement for acid or copper additives. In the reaction with arene-sulfonyl chloride, palladium is used in combination with copper. A plausible mechanism involves initial cupration of the benzoxazole followed by copper—palladium exchange and oxidative addition of the sulfonyl chloride to palladium to give (84). This intermediate may lose sulfur dioxide to give an aryl palladium species, which, on reductive elimination, yields 2-arylbenzoxazole. The arylation of benzoxazoles and benzthiazoles with aryl boronic acids is also catalysed by a combination of palladium... 

General Discussion. Various kinetic and reactivity studies have been performed using TsBr alone or in comparison with other arene sulfonyl halides. Most of the literature describes the use of this reagent to initiate free radical ring formation, predominantly for five-membered ring systems. There are, however, reports of its use in vinyl sulfone and thiolsulfonate formation and in halogenation reactions. 

Unfortunately, other A7-substituted phenyl ketimines 93a-e afforded lower ee values compared with 90. The iV-benzyl ketimine 93e was also proven to be an unsuitable substrate using 91 as catalyst. The authors found that the arene sulfonyl group on N4 and the 2-carboxamide groups were crucial for the high enantiose-lectivity of the process and the efficiency of the catalytic system. 

Across carbon multiple bonds The [2-1-2] cycloaddition reaction of isothiocyanates occurs readily with activated olefins, such as enamines and ketene acetals. For example, arene-sulfonyl isothiocyanates undergo a regiospecific [2-1-2] cycloaddition reaction with vinyl ethers at 50 °C to give 2-thietan imines 24. ... 

This diminished the effectiveness of fully protected intermediates unless rapid deprotection could be carried out. It was much better if a lower degree of protection was utilized. Thus, a set of methods for activation of monoesters, for example, adenosine 5 -phosphate (AMP), were developed (Scheme 4), Dicyclohexylcarbodiimide (8) and arene-sulfonyl chlorides led rapidly to symmetrical pyrophosphates (8) (11). Michelson found that (PhO)2 PO Cl gave activated intermediates (9) that were on the verge of stability, but could be put into reaction with a second component to obtain the required unsymmetrical polyphosphate (10) (12). The complete solution to the problem depended on forming phosphoramidic acids (11) (and related structures), stable in themselves but capable of undergoing reaction by cleavage of the P—bond (Scheme A) (6,13). Phosphates are better nucleophiles than... 

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