Diene Derivative with High Reactivity for Diels-Alder Reaction

trans-3-(tert-Butyldimethylsilyloxy)-N,N-dimethyl-1,3-butadiene-1-amine (1), also known as Rawal’s diene,¹⁾ is a building block used in (hetero) Diels-Alder reactions. It has been reported that the reactivity of 1 is thousand times more when compared to Danishefsky-Kitahara diene because of higher HOMO level²⁾ of 1 to that of Danishefsky-Kitahara diene. Additionally, the given silyl enol ether is hydrolyzed by acid to afford an α,β-unsaturated ketone. There have been many reports of the total syntheses of natural products using 1, which suggests the usefulness of this method.