Copper‐Catalyzed [3+2] Cycloaddition Reactions of Isocyanoacetates with Phosphaalkynes to Prepare 1,3‐Azaphospholes

Building bridges: A copper‐catalyzed synthesis of phosphorus‐ and nitrogen‐containing heterocycles is described. Cycloaddition reactions of various isocyanoacetates with phosphaalkynes in the presence of copper bromide, bis(diphenylphosphino)methane, and potassium carbonate afford the corresponding 1,3‐azaphospholes in high yields with complete selectivity. Dicopper complexes were identified as active species.

Abstract

A novel copper‐catalyzed synthetic method is described for phosphorous‐ and nitrogen‐containing heterocycles such as 1,3‐azaphospholes. Cycloaddition reactions of various isocyanoacetates with phosphaalkynes in the presence of copper bromide, bis(diphenylphosphino)methane (dppm), and potassium carbonate afford the corresponding 1,3‐azaphospholes in high yields with complete selectivity. Some dppm‐bridged dicopper complexes were identified as active species for the formation of 1,3‐azaphospholes.

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