1,3-Butadienyl-thiocyanate in der <i>Diels-Alder</i>-Reaktion mit anschliessender [3,3]-sigmatroper Umlagerung

<i>(E)</i>- and (Z)-1,3-Butadienyl thiocyanates <b>3</b>, <b>4</b>, and <b>12-15</b> have been synthesized selectively. Their use as dienes for <i>Diels-Alder</i> reactions followed by a [3,3]-sigmatropic shift to obtain an isomeric isothiocyanate has been studied. The butadienyl thiocyanates are, unfortunately, not very reactive in <i>Diels-Alder</i> reactions. This disadvantage can be overcome, if a trapping reaction with EtOH is added to the two-step sequence. This sequence allows to get good yields of the O-ethyl thiocarbamates <b>18-23</b>, even if the first two reactions have not favorable equilibrium constants.