3‐Trimethylsilylacrylic Acid as an Acetylene Equivalent in Diels‐Alder Reactions; Olefins via Anodic Decarboxylation‐Desilylation

For the preparation of 1,4-cyclohexadienes via [4 + 2]-cycloadditions, synthetic equivalents for acetylene are desired that are more dienophilic and less pressure-sensitive. The silylcarboxylic acid 1 offers several advantages: It adds smoothly, e.g., to cyclopentadiene or isoprene to afford 2 and 3 or 4 and 5; the “protecting groups” can be removed anodically to afford norbornadiene or 1-methyl-1,4-cyclohexadiene.