Sulfones rearrangement

Principally, both unifold and twofold transformation types ensue in these cases. A unifold transformation occurs in the case of the rearrangement of cumyl benzenesulfinate, which arises from the conversion of cumyl hydroperoxide with benzenesulfenyl chloride23 (equation 2). Closely related sulfoxylate-sulfone rearrangements, which pass intermediate sulfinate steps similarly, are equally known24,25. 

Baldwin and coworkers73 have used the allylic sulfinate to sulfone rearrangement (13 to 14) for the development of a convenient route to the dihydroxyacetone unit, an... 

The above studies show that dithionite reduction of mitosenes results in the formation of lOa-sulfite esters as well as sulfonates. The presence of the excellent sulfite-leaving group at the mitosene 1 Oa-position suggests that alkylation reactions at this position could still occur. The subsequent sulfite to sulfonate rearrangement results in loss of alkylation capability by this position. 

The sulfenate-sulfoxide and sulfinate-sulfone rearrangements are very reliable and proceed with complete syn stereoselectivity17, ls. The allenic sulfoxides can be used for the synthesis of chiral alkylallenes with retention of configuration (see Section 1.1.3.). The relative configuration at sulfur in the allenic sulfoxides is not important for further synthetic purposes and racemization at sulfur is often observed without affecting the allenic axial dissymmetry. 

A palladium-catalyzed allylic sulfonate-sulfone rearrangement with chiral sulfonates produced 92% optical yields (equation 3S9).448 449 Presumably, the optically active sulfonate induces chirality in the oxidative addition by Pd° in these reactions. 

A report on the chirality transfer from sulfur to carbon in the allylic sulfinate to sulfone rearrangement has appeared in which a series of 5-configurated (E)- and (Z)-l-(4-methylphen-ylsulfinyloxy)-2-alkenes 2 were converted to the sulfones 3132. 

The chemistry of imidosulfinates is vastly unexplored [10] and nothing is known to date about the behavior of 0-allyl imidosulfinates in particular. By comparison with the known process C (Chart 1), the sulfinate-sulfone rearrangement (Sect. 2.2), it seems rather promising to try a new sulfoximine synthesis based on that rearrangement. 

In addition to the above-mentioned 1,3-chirality transfer, another mode of transferring centro chirality from one atom to the other is the S C transfer. This feature of the reaction has already been discussed by Mislow in his 1968 paper [40], where he delineates all important stereochemical aspects of [2,3]-sigmatropic rearrangements using the sulfoxide-sulfenate rearrangement as an example. For the sulfinate-sulfone rearrangement under consideration here, the work of Hiroi in the early 1980s should be mentioned (Scheme 16) [44,... 

Synthetic Utility of the Propargylic Sulfinate-to-Sulfone Rearrangements. 91... 

The related sulfone 189, when treated with sodium hydroxide in acetone, smoothly rearranged into sulfinic acid 190 (isolated as methyl sulfone 191, 70% yield) at room temperature. As expected, the sulfone rearranged more readily than the sulfide. 

Selective a-addition of C4-substituted azlactones was observed in the Michael addition-[1,2]-sulfone rearrangement sequence, which proceeded with moderate to good enantioselectivity (Scheme 20) [37]. Although 5% of the y-addition product was detected in the reaction with triethylamine as a base, the use of bifunctional amino-thiourea 20 was pivotal for achieving complete site-selectivity and high enantioselectivity. 

Quintard A, Alexakis A. 1,2-Sulfone rearrangement in organocatalytic reactions. Org. Biomol. Chem. 2011 9(5) 1407-1418. 

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