Diels-Alder Syntheses with 1,4-Di-tert-butoxy-1,3-butadiene

Article abstract of DOI:10.1021/jo00166a033

The title compound (DTBU) enters into <4+2> cycloadditions with fumaronitrile, tetracyanoethene, maleic anhydride, diethyl azodicarboxylate, 1,2-dibenzoylethene, dimethyl acetylenedicarboxylate, p-benzoquinone, 2-carbomethoxybenzoquinone, 2-methylbenzoquinone, 1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, and 5-hydroxy-1,4-naphthoquinone.When prepared the DTBU isomers are present in the ratio E,Z:Z,Z:E,E = 45:45:10.Of these, Z,Z-DTBU appears to be unreactive.In several cases where multible Diels-Alder products were possible, two related to E,Z- or E,E-DTBU were obtained.A connection between 1H NMR data (δ and J) and stereochemical configuration and conformation was elaborated for adducts of DTBU with p-benzoquinones or maleic anhydride.