Bisketene Equivalents as Diels–Alder Dienes

2,5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents 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,...