3.5- Bis phenylsulfonyl

Heating 3,4-bis(phenylsulfonyl)furoxan with a solution of sodium butoxide in butanol followed by reduction with trimethyl phosphite gives furazan 281 (Scheme 183). Compound 281 was converted into dialkoxy derivative 282 with the lithium salt of ( )-l-azabicyclo[2.2.2]octan-3-ol in 33% overall yield (96W012711, 97EUP773021, 98JMC379). 

Few reactions of sulfonylfuroxans with olefins have been reported. Depending on the substituents at the furoxan ring, nature of dipolarophile, and temperature, different types of products may be obtained. It is relatively simple to cyclore-vert disulfonylfuroxans to a-sulfonyl nitrile oxides on thermolysis (81TL3371, 85T727). These nitrile oxides were trapped by dipolarophiles to yield sulfonyl-substituted isoxazole derivatives. For example, 3,4-bis(phenylsulfonyl)furoxan reacts with an excess of styrene in xylene under reflux to afford the corresponding isoxazoline 290 (Scheme 189). 

Reaction of 3,4-bis(phenylsulfonyl)-l,2,5-oxadiazole oxide isomers with ethanol and ethanethiol in basic medium gave the expected alkoxy- and alkylthio-substituted (benzenesulfonyl)furoxans, respectively <1996JHC327, 1997FES405>. Nucleophilic substitution of the sulfonyl group of 3,4-bis-(benzenesulfonyl)furoxan 222 in the presence of aqueous NaOH in tetrahydrofuran (THF) furnished the corresponding 3 -0-(3-benzenesulfonylfur-oxan-4-yl) derivative 223 in 79-92% yield (Equation 44) <2004JME1840>. 

Analog reagiert 3,4-Di-tert.-butyl-furazan-2-oxid mit Alkenen442bzw. 3,4-Bis-[phenylsulfonyl]-furazan-2-oxid443 mit Alkenen bzw. Alkinen444 ... 

Novi and coworkers124 have shown that the reaction of 2,3-bis(phenylsulfonyl)-l,4-dimethylbenzene with sodium benzenethiolate in dimethyl sulfoxide yields a mixture of substitution, cyclization and reduction products when subjected at room temperature to photostimulation by a sunlamp. These authors proposed a double chain mechanism (Scheme 17) to explain the observed products. This mechanism is supported by a set of carefully designed experiments125. The addition of PhSH, a good hydrogen atom donor, increases the percent of reduction products. When the substitution process can effectively compete with the two other processes, the increase in the relative yield of substitution (e.g., with five molar equivalents of benzenethiolate) parallels the decrease in those of both cyclization and reduction products. This suggests a common intermediate leading to the three different products. This intermediate could either be the radical anion formed by electron transfer to 2,3-bis(phenylsulfonyl)-l,4-dimethylbenzene or the a radical formed... 

However, it is interesting that the same reaction with bis(phenylsulfonyl)methane in the presence of NaH afforded 3-nucleophile-substituted-2-(phenylsulfonyl)-l-pro-pene 197 and the expected 2-[bis(phenylsulfonyl)methyl]-2-propenyl sulfone 198 in 94 and 4% yields, respectively. A similar reaction with methyl phenylsulfonylacetate afforded 199 and 200 in a ratio of 2 1. 

Commercially available bis(phenylsulfonyl)amine (59.4 g, 0.2 mol) in MeCN (150mL) at - 40 C in the presence of powdered NaF in an ambient pressure reactor was reacted with 10% F2/N2 (7.6 g, 0.2 mol) for 3 h. An excess of F2 must be avoided since it leads to fluorination of the aromatic rings. After evaporation of the solvent, the crude mixture was purified by recrystallization (Et20) or by column chromatography (silica gel, CH2C12). A-Fluorobis(phenylsulfonyl)amine was obtained in 70% average yield as a colorless solid which melts without decomposition at 114—116 JC and which is thermally stable up to 180°C. 

The phototransformation of l,2-bis(phenylsulfonyl)-3,4,5,6-tetramethylbenzene into 2,3,4,5-(e(rame(hyldibcnzo(hiophcne-5,5-dioxide upon the action of arylthiolates should also be mentioned. The yield of dibenzothiophene-5,5-dioxide is more than 90%. The addition of m-dinitrobenzene prevents the cyclization. The reaction proceeds as shown in Scheme 6-34 (Novi et al. 1982). 

ANIONIC ELECTROCYCLIZATION USING 2,3-BIS(PHENYLSULFONYL)-1,3-BUTADIENE trans-4,7,7-... 

B. 2,3-Bis(phenylsulfonyl)-1,3-butadiene (1). A solution of 17.0 g of 2,3-bis(phenylsulfinyl)-l.3-butadiene (56.3 mmol) and 34 mL of hydrogen peroxide (30-35%) (Note 4) in 170 mL of glacial acetic acid is placed in a 500-mL, three-necked flask equipped with a reflux condenser and thermometer. The solution is warmed using an oil bath such that a reaction temperature of 90°C is maintained for 5 hr (Note 5). To the hot solution is added 40 mL of water and the mixture is allowed to stand at room temperature for 12 hr. The resulting precipitate is collected, washed with water (50 mL), cold methanol (30 mL), and ether (100 mL). The filter cake (13.9 g) is dissolved in 100 mL of hot dichloromethane and 100 mL of hexane is added slowly. After standing at 25°C for 1 day, the crystalline solid is collected and washed with 100 mL of ether to give 11.6 g (61%) of 2,3-bis(phenylsulfonyl)-1,3-butadiene (Note 6).2 Concentration and recrystallization of the mother liquor affords an additional 1.7 g (9%) of the disulfone. 

D. trans-4,7,7-Tricarbomethoxy-2-phenylsulfonylbicyclo[3.3.0]oct-1-ene. In a flame-dried, 2-L, three-necked, round-bottomed flask equipped with a magnetic stirrer, dropping funnel, and nitrogen inlet, is placed 1.44 g of sodium hydride (60% in oil, 36.0 mmol) which has been washed twice with 50 mL of hexane and then suspended In 500 mL of anhydrous THF. To the above mixture is added 7.59 g (33.0 mmol) of dimethyl (E)-5-methoxycarbonyl-2-hexenedioate in 50 mL of THF. After being stirred at 0°C for 30 min, a solution containing 10.02 g (30.0 mmol) of 2,3-bis(phenylsulfonyl)-1,3-butadiene in 900 mL of anhydrous THF is added over 30 min. The solution is stirred for 10 min at 0°C and then quenched with 100 mL of a saturated aqueous ammonium chloride solution. The solvent is removed under reduced pressure, and... 

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