Grignard reagents with sulfonyl chlorides

The reaction of Grignard reagents with sulfonyl chlorides also yields sulfones. 

Sulfinic acids are generally prepared by reduction of the readily available sulfonyl chlorides with zinc in neutral or basic aqueous solution.2 The reduction may also sometimes be achieved by treatment with tin(II) chloride or sodium sulfite (Scheme 1). Another route involves reaction of a Grignard reagent with sulfur dioxide (Scheme 1). 

The oxidative dimerization of the anion of methyl phenyl sulfone (from a Grignard reagent) in ethereal solution in the presence of cupric chloride in 5% yield has been reported47. Despite the reported48 poor stability of the a-sulfonyl C-centered radicals, Julia and coworkers49 provoked the dimerization (in 13 to 56% yields) of the lithiated carbanion of alkyl phenyl sulfones using cupric salts as oxidants. The best results are obtained with cupric triflates in THF-isobutyronitrile medium (56% yield for R = H). For allyl phenyl sulfones the coupling in the 3-3 mode is predominant. 

Grignard reagents convert aromatic sulfonyl chlorides or aromatic sulfonates to sulfones. Aromatic sulfonates have also been converted to sulfones with organolithium compounds.1745 Vinylic and allylic sulfones have been prepared by treatment of sulfonyl chlorides with a vinylic or allylic stannane and a palladium-complex catalyst.1746 Alkynyl sulfones can be prepared by treatment of sulfonyl chlorides with trimethylsilylalkynes, with an AICL catalyst.1747... 

Thiophenethiols are prepared by reduction of the sulfonyl chlorides or, more conveniently, by the reaction of Grignard reagents or thienyllithium compounds with sulfur. They have also been obtained by cleavage or thienyl alkyl sulfides with sodium in liquid ammonia. 3-Thiophenethiol is a by-product in the commercial thiophene synthesis. Thiophenethiols have recently also been prepared by a synthesis involving Friedel-Crafts reaction of 2,4-dinitrobenzenesulfenyl chloride with thiophenes, followed by basic cleavage of the resulting sulfide. ... 

Several thiols occur naturally for example, skunk secretion contains 3-methyll-butanethiol and cut onions evolve 1-propanethiol, and the thiol group of the natural amino acid cysteine plays a vital role in the biochemistry of proteins and enzymes (see Introduction, p. 2). Primary and secondary thiols may be prepared from alkyl halides (RX) by reaction with excess sodium thiolate (SN2 nucleophilic substitution by HST) or via the Grignard reagent and reaction with sulfur. Tertiary thiols can be obtained in good yields by addition of hydrogen sulfide to a suitable alkene. Thiols can also be prepared by reduction of sulfonyl chlorides (Scheme l).la,2a... 

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. ... 

Chiral Lewis acids derived from complexes between copper(I) chloride with phosphino sulfenyl ferrocenes are efficient catalysts for enantioselective aza-Diels-Alder reaction of A-sulfonyl imines with Danishefsky-type dienes (eq 47), and asymmetric conjugate addition of Grignard reagents to cyclic enones (eq 48).136... 

Volla CMR, Vogel P. Iron-catalyzed desulfinylative C—C cross-coupling reactions of sulfonyl chlorides with Grignard reagents. Awgew. Chem. Int. Ed. 2008 47 1305-1307. 

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