Gold-Catalyzed Cyclization of 2-Alkynylaldehyde Cyclic Acetals via Hydride Shift for the Synthesis of Indenone Derivatives
Tsuyoshi Yamada, Kwihwan Park, Takumu Tachikawa, Akiko Fujii, Matthias Rudolph, A. Stephen K. Hashmi, Hironao Sajiki
Abstract
An efficient gold-catalyzed cyclization of 2-alkynylaldehyde cyclic acetals has been developed for the synthesis of indenone derivatives. A wide variety of functionalized indenone derivatives can be obtained in good-to-excellent yields. HMBC and NOESY NMR analyses and mechanistic elucidation experiments revealed that the cyclization occurs via a 1,5-H shift. The cyclic acetal group promoted the 1,5-H shift by activating the benzylic C-H bond and preventing the migration of the alkoxy group by tethering both alkoxy groups.
Topics & Concepts
ChemistryAlkoxy groupHydrideCatalysisAcetalCombinatorial chemistryStereochemistryOrganic chemistryMetalAlkylCatalytic Alkyne ReactionsSynthetic Organic Chemistry MethodsCatalytic C–H Functionalization Methods