Benzenesulfinate anion

Evidence for a Michael addition of a nucleophile to alkenyl(phenyl)iodonium salts at the Cp atom has now been reported for the first time. Nucleophilic vinylic substitutions of (Z)-(/3-bromoalkenyl)iodonium tetrafiuoroborates (161) and its (Z)-(/3-chloroalkenyl) analogue with sodium benzenesulfinate in THE afforded stereoselectively (Z)-l,2-bis(benzenesulfonyl)alkene (163) with retention of configuration. Intermediate formation of (Z)-[/3-(benzenesulfonyl)alkenyl]iodonium salt (162) in these reactions was established by NMR experiments in CDCI3. The formation of (Z)-(162) involves a hitherto unobserved Michael addition of benzenesulfinate anion to the alkenyliodonium salts at the Cp atom, followed by halogen extrusion. ... 

When migratory aptitudes of a-substituents of alkylidene carbenes are relatively poor, the MCI pathway competes with the MCR reaction. Reaction of the alkynyliodane with benzenesulfinate anion in water leads to a mixture of the MCI and the MCR products, because of a moderate migratory aptitude of aryl-sulfonylgroups [Eq. (114)] [170]. 

The Michael reaction of sulfonyl carbanions with a,p-unsaturated esters provides a useful preparation of cyclopropane esters, as shown in Scheme 47. In this sequence, the sulfonyl carbanion undergoes conjugate 1,4-addition to the a,p-unsaturated carbonyl compound followed by intramolecular elimination of the benzenesulfinate anion (Scheme 47). 

Reaction of 2-chloromethyl-4//-pyrido[l,2-u]pyrimidine-4-one 162 with various nitronate anions (4 equiv) under phase-transfer conditions with BU4NOH in H2O and CH2CI2 under photo-stimulation gave 2-ethylenic derivatives 164 (01H(55)535). These alkenes 164 were formed by single electron transfer C-alkylation and base-promoted HNO2 elimination from 163. When the ethylenic derivative 164 (R = R ) was unsymmetrical, only the E isomer was isolated. Compound 162 was treated with S-nucleophiles (sodium salt of benzyl mercaptan and benzenesulfinic acid) and the lithium salt of 4-hydroxycoumarin to give compounds 165-167, respectively. 

Ley [426] has reported a case of spontaneous elimination of benzenesulfinic acid in the reactions of the anion of 2-benzenesulfonyl-tetrahydropyran with electrophiles. A convenient synthesis of spiroketals... 

Reduction of the mixture of erythro- and t/rreo-sulfones with Na(Hg) leads stere-oselectively to the trans-alkene, indicating that the alkene-forming steps for both diastereomeric sulfones must involve a common intermediate. The (E)-selectivity of the elimination step may involve two successive electron transfers from the sodium to the sulfone, resulting in the loss of benzenesulfinate. The anion that is formed must have a lifetime sufficient to equilibrate and assume the low-energy conformation, which places (1) the p-orbital of the carbanion antiperiplanar to the acetoxy leaving group and (2) the bulky substituents as far apart as possible. Therefore, the... 

The mixed phosphonium-iodonium ylides (Section 2.1.10.1), such as the tosylate 796, represent a useful class of reagents that combine in one molecule the synthetic advantages of a phosphonium ylide and an iodonium salt [1091-1100]. Specifically, phosphorane-derived phenyliodonium tosylate 796 reacts with soft nucleophiles, such as iodide, bromide, benzenesulfinate and thiophenolate anions, to form selectively the respective a-functionalized phosphonium ylides 797 (Scheme 3.315), which can be further converted into alkenes (e.g., 798) by the Wittig reaction with aldehydes [1092]. The analogous arsonium-iodonium ylides have a similar reactivity toward nucleophiles [1091, 1094, 1101]. 

Aromatic Annulation. 7-Methoxy-3-(phenylsulfonyl)-l(3Y/)-isobenzofuranone (1) can be deprotonated at —78 °C with either lithium diisopropylamide or lithium ferf-butoxide to form a soluble yellow anion which can be utilized as an effective nucleophile in the Michael reaction. The initial anionic adduct cyclizes with concomitant elimination of benzenesulfinic acid to yield a 1,4-dihydroxynaphthalene which is unambiguously disubstituted at the 2- and 3-positions (eq l). ... 

The anion of Cj5 sulfone (13) underwent a nucleophilic reaction with bromide (638) subsequent elimination of benzenesulfinic acid from the product gave the butenolide (639). The structure of (639) is based on the carbon skeleton of (all- )-retinoic acid (3) (Welch and Gruber, 1982), as is the dihydropyrone... 

This chapter comprises a number of organotin halides containing anions like tetraphenyloborate, benzenesulfinate and perchlorate. The terpyridine complexes are proposed to contain six-coordinated tin. The compounds are prepared by the following methods. 

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