Diastereoselective Synthesis of Tetrasubstituted Olefins from Internal Alkynes via Three-Component Reaction Using a Heterogeneous Organometallic Triptycene-Based Porous Palladium Catalyst.

Abstract

In this work, we report the design, synthesis, and application of a hyper-crosslinked heterogeneous organometallic porous organic polymer (Pd@TP-DPPF) catalyst for the efficient and sustainable dicarbofunctionalization of internal alkynes via a facile three-component reaction. This strategy enables the highly trans-selective syntheses of tetrasubstituted olefins in excellent yields. The catalyst is constructed by integrating triptycene (TP) and 1,1'-bis(diphenylphosphino)ferrocene (DPPF) into a robust palladium-based porous framework, resulting in a unique heterogeneous system that efficiently mediates the coupling of internal alkynes with readily available iodoarenes and aryl/methyl boronic acids. This methodology also offers a versatile strategy for the syntheses of complex and valuable trans-selective alkenylsilanes under mild conditions, with high atom economy. Mechanistic studies support a trans-selective transformation pathway facilitated by the cooperative role of the polymer support and the palladium center. Importantly, the Pd@TP-DPPF catalyst exhibits excellent recyclability, air/moisture stability, and operational simplicity, making it highly suitable for large-scale and environmentally conscious synthetic applications. This work not only addresses a long-standing challenge in the synthesis of highly substituted olefins but also exemplifies the principles of green chemistry through catalyst reusability, waste minimization, and efficient multicomponent transformation.