Masked Bisketenes as Diels–Alder Dienes
2,5-Bis(tert-butyldimethylsilyloxy)furans are established as masked vicinal bisketenes for application as dienes in the Diels–Alder reaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels–Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from acetylenic dienophiles, including benzynes, is also demonstrated, and 2,5-bis(tert-butyldimethylsilyloxy)pyrroles are established as competent dienes for the synthesis of para-iminoquinones. Application in natural product synthesis enables gram-scale access to the neuroprotective agent (±)-indanostatin.