Highly Efficient Conversion of Propargylic Alcohols and Propargylic Amines with CO2 Activated by Noble‐Metal‐Free Catalyst Cu2O@ZIF‐8

Abstract

AbstractThe cyclization reactions of propargylic alcohols and propargylic amines with CO2 are important in industrial applications, but it was a great challenge that non‐noble‐metal catalysts catalyzed both reactions under mild conditions. Herein, the catalyst Cu2O@ZIF‐8 was prepared by encapsulating Cu2O nanoparticles into robust ZIF‐8, and it can effectively catalyze the cyclization of both propargylic alcohols and propargylic amines with CO2 into valuable α‐alkylidene cyclic carbonates and oxazolidinones with turnover numbers (TONs) of 12.1 and 19.6, which can be recycled at least five times. The mechanisms were further uncovered by NMR, FTIR, 13C isotope‐labeling experiments and DFT calculations, in which Cu2O and DBU can synergistically activate the C≡C bond and the hydroxy/amino group of substrates. Importantly, it is the first example of a noble‐metal‐free catalyst that can catalyze both propargylic alcohols and propargylic amines with CO2 simultaneously.