Selective [5,5]‐Sigmatropic Rearrangement via Electrophilic Assembly of Aryl Sulfoxides with Allyl Nitriles

Aromatic [5,5]‐sigmatropic rearrangement is an appealing protocol for accessing 1,4‐substituted arenes. However, such a protocol has not been well utilized in organic synthesis, because it often suffers from the difficulties in the synthesis of substrates, selectivity issues, and limited substrate scopes. Herein, we describe a new [5,5]‐sigmatropic reaction by utilizing readily available aryl sulfoxides and allyl nitriles. Unlike conventional [5,5]‐sigmatropic reactions, this reaction features mild conditions, high chemo‐ and regioselectivity, excellent functional group compatibility and broad substrate scope. Computational studies suggested that the success of the reaction can be attributed to the selective electrophilic assembling of rearrangement precursors in which a linear ‐C=C=N‐ linkage favors [5,5]‐sigmatropic rearrangement over the competitive [3,3]‐sigmatropic rearrangement.

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