134792-09-9Relevant articles and documents
Stereochemistry of the olefin formation from anti and syn heterocyclic β-hydroxy sulfones.
Baudin, J. B.,Hareau, G.,Julia, S. A.,Ruel, O.
, p. 336 - 357 (2007/10/02)
Reaction of aldehydes R2-CHO with the new lithio derivatives of 2-benzothiazoles or pyridines R1-CH2-SO2-Het afforded the corresponding β-hydroxy sulfones which are stable in the pyridine series and generally unstable in the benzothiazole series except for anti derivatives 10a and 20c. t-Butyl-dimethyl silyl ethers of all the heterocyclic β-hydroxy sulfones have been obtained by oxidation of the corresponding anti and syn sulfides, which have been stereoselectively prepared from the epoxides 17, 19, 21 and 23.The lithium or tetrabutylammonium alkoxides of heterocyclic β-hydroxy sulfones undergo an intramolecular addition to the neighboring C=N group followed by an S to O benzothiazole (or pyridine) transfer, and simultaneous extrusion of sulfur dioxide, ejection of benzothiazol-2(3H)-one anion and formation of the corresponding olefins.From the data of twenty cases studied, it can be concluded that the final elimination is entirely antiperiplanar only for the alkoxides of β-hydroxy-BT- or Pyr-sulfones anti or syn bearing saturated aliphatic chains R1 and R2 and for anti derivatives with R1 = R2 = C6H5.Due to their equilibration however, the alkoxides of numerous derivatives of heterocyclic (3-methylbut-2-enyl) or (phenylmethyl) sulfones do not follow entirely the above antiperiplanar elimination. Keywords: heteroaromatic sulfones / intramolecular ipso reaction / organolithium derivatives / stereochemistry / eliminations / olefination
