Hydrated [3+2] Cyclotelomerization of Butafulvenes to Create Multiple Contiguous Fully Substituted Carbon Centers

Angew Chem Int Ed Engl. 2024 Feb 5;63(6):e202317299. doi: 10.1002/anie.202317299. Epub 2024 Jan 2.

Abstract

The construction of multiple continuous fully substituted carbon centers, which serve as unique structural motif in natural products, is a challenging topic in organic synthesis. Herein, we report a hydrated [3+2] cyclotelomerization of butafulvenes to create contiguous fully substituted carbon backbone. In the presence of scandium triflate, all-carbon skeleton with spiro fused tricyclic ring can be constructed in high diastereoselectivity by utilizing butafulvene as the synthon. Mechanistic studies suggest that this atom-economic reaction probably proceeds through a synergistic process containing butafulvenes dimerization and nucleophilic attack by water. In addition, the tricyclic product can undergo a series of synthetic derivatizations, which highlights the potential applications of this strategy. The recyclability of Sc(OTf)3 has also been demonstrated to show its robust performance in this hydrated cyclotelomerization.

Keywords: Butafulvene; Cyclotelomerization; Fully Substituted Carbon; Hydration; Spiro Compound.