Csp3-P versus Csp2-P Bond Formation: Catalyst-Controlled Highly Regioselective Tandem Reaction of Ene-Yne-Ketones with H-Phosphonates

Under copper-catalyzed or base-promoted conditions, a wide range of ene-yne-ketones react with H-phosphonates to afford various phosphorylated furans in good yields. A copper carbene generation or a Michael addition is proposed as the key step in the selective construction of the Csp(3)-P or Csp(2)-P bond, which is supported by carbene capture reactions and interval P-31 NMR experiments. Furthermore, this method features inexpensive metal catalysts, no usage of oxidant, and high atom economy, which make it attractive and practical.