Description:
<jats:title>Abstract</jats:title><jats:p>The reaction of 2,2‐dimethyl‐5‐(1,2‐epoxypropyl)cyclohexanone (<jats:bold>7</jats:bold>) with <jats:italic>t</jats:italic>‐BuOK in DMSO furnished a small amount of 5‐(1‐hydroxyprop‐2‐enyl)‐2,2‐dimethylcyclohexanone (<jats:bold>12</jats:bold>) and the 4 unexpected products <jats:bold>13–16</jats:bold> which contain one to three additional C‐atoms (<jats:italic>Scheme 2</jats:italic>). The relative configuration of the major product 1‐(4′,4′‐dimethyl‐2′,3′‐dimethylidenecyclohexyl)propane‐1,2‐diol (<jats:bold>15</jats:bold>) was shown to be 1<jats:italic>RS</jats:italic>, 2<jats:italic>RS</jats:italic>,1′<jats:italic>SR via</jats:italic> NOE measurements performed on a derivative thereof. A crossover experiment in DMSO/[<jats:sup>13</jats:sup>C<jats:sub>2</jats:sub>]DMSO 1:1 as solvent showed that the two additional C‐atoms of this product originate from a single molecule of DMSO (<jats:italic>Scheme 5</jats:italic>). A tentative mechanistic scheme, consistent with all experimental observations, is proposed which involves a [2,3]‐sigmatropic rearrangement of an (allylsulfinyl)methanide to a sulfenic acid as one of the key steps (<jats:bold>V → 24</jats:bold>, <jats:italic>Scheme 8</jats:italic>). We corroborated part of this hypothetic scheme by taking recourse to a model compound (7‐(methylsulfinyl)‐<jats:italic>p</jats:italic>‐mentha‐1,8‐diene (<jats:bold>32/33</jats:bold>), readily prepared in two steps from perilla alcohol (<jats:bold>30</jats:bold>)), which reacted as predicted by the proposed mechanism (<jats:italic>Schemes 9</jats:italic> and <jats:italic>10</jats:italic>).</jats:p>