posted on 2022-12-23, 21:13authored byYue-You Chen, Chen-Dong Zhou, Xing-Tong Li, Ting-You Yang, Wen-Yong Han, Nan-Wei Wan, Yong-Zheng Chen, Bao-Dong Cui
A cooperative
tertiary amine/palladium-catalyzed sequential reaction
process, proceeding via a [4 + 3] cyclization of isatin-derived Morita-Baylis-Hillman
Expansion (MBH) carbonates
and tert-butyl 2-(hydroxymethyl)allyl carbonates
followed by a [1,3]-rearrangement, has been found and developed. A
range of structurally diverse spiro[methylene cyclopentane-1,3′-oxindolines]
bearing two adjacent β,γ-acyl quaternary carbon stereocenters,
which are difficult to obtain by conventional strategies, were obtained
in good yields. Further synthetic utility of this protocol is highlighted
by its excellent regio- and stereocontrol as well as the large-scale
synthesis and diverse functional transformations of the synthetic
compounds. Moreover, the control experiments probably established
the plausible mechanism for this sequential [4 + 3] cyclization/[1,3]-rearrangement
process.