We have developed a highlyselectiveone-pot method for the synthesis of (E)-vinyl sulfones and sulfoxides from thiols with terminal alkynes. The sulfones and sulfoxides could be obtained with excellent selectivity in good isolated yields. It is simple, efficient and environmentally benign, and metal-free. The mechanism for the formation of the (E)-vinyl sulfones was also proposed.
Asymmetric Claisen Rearrangements on Chiral Vinyl Sulfoxides
作者:Roberto Fernández de la Pradilla、Carlos Montero、Mariola Tortosa、Alma Viso
DOI:10.1002/chem.200801680
日期:2009.1.5
Highly diastereoselective Claisen rearrangements of acyclic allyl vinyl ethers bearing a chiralsulfoxide at C‐5 provide γ‐δ‐unsaturated aldehydes or ketones with up to two consecutive asymmetric centers in the molecule whilst preserving a useful vinyl sulfoxide. The reactivity of related vinyl sulfides and sulfones has also been examined in this work.
alk-1-enyl sulfoxides is reported. The reaction between alane–pyridine complexes, triphenylphosphine, and sulfonyl chlorides affords the title products in good to excellent yields (70–94%) in short reaction times using mild conditions. The optimal ratio between reagents (alane–pyridine/PPh3/sulfonyl chloride 1.00/1.35/0.92) was obtained performing a chemiometric analysis. A rationale for the reaction was
A new synthetic approach to aryl and alkyl α,β-unsaturated sulfoxides is reported. The reaction has been optimized with respect to solvent, temperature, and ratio of reagents. The described procedure allows the synthesis of the title compounds in good yields (71-82%) starting from readily available reagents, in a cost-effective procedure.
The unprecedented radical β-elimination of vinylsulfoxides opens a new access to functionalized di- and trisubstituted allenes. The radical precursors are obtained in two steps from a carbonyl derivative and a vinylsulfoxide. The radical translocation trick can also be used to trigger the β-elimination of the sulfinyl radical.