Chalcogen bonding catalysis has recently emerged as a new platform in organic synthesis, enabling the achievement of a diverse array of reactions. All of these chalcogen bonding catalyzed reactions rely on the interactions with lone-pair and π electrons. Owing to the lack of effective interaction with σ electrons, the activation of C-C σ-bonds by chalcogen bonding catalysts remains one of the most noteworthy unrealized challenges in this field. Here, we describe the activation of the C-C σ-bond of 1.1.1propellane by chalcogen bonding, enabling the insertion of a cyclobutyl moiety into cyclopropenones to construct spiro3.3heptanes. Conventionally, the activation of the C-C σ-bond of 1.1.1propellane was enabled by transition metals; however, the previously active transition-metal catalysts were ineffective in facilitating the insertion reaction between 1.1.1propellane and cyclopropenones. While the activation of the C-C σ-bond of 1.1.1propellane by the main-group catalyst is elusive, conversely, this research relies on using chalcogen bonding to activate 1.1.1propellane and to stabilize the alkyl carbene intermediate. Mechanistic investigation suggests that a dual catalysis mode is operative. This method is highly efficient, and the reactions were generally completed within several minutes to give spiro3.3heptanes using 2.5 mol % catalyst at 0 °C or room temperature.
Ziqiang Zhao (Fri,) studied this question.