Michael Addition of 3-Oxo-3-phenylpropanenitrile to Linear Conjugated Enynones: Approach to Polyfunctional δ-Diketones as Precursors for Heterocycle Synthesis

Reaction of linear conjugated enynones, 1,5-diarylpent-2-en-4-yn-1-ones [(ArC)-C-1 & EQUIV;CCH=CHC(=O)Ar-2], with 3-oxo-3-phenylpropanenitrile (NCCH2COPh) in the presence of sodium methoxide MeONa as a base in MeOH at room temperature for 4-26 h affords polyfunctional delta-diketones as a product of regioselective Michael addition to the double carbon-carbon bond of starting enynones. The delta-diketones have been formed as mixtures of two diastereomers in a ratio of 2.5:1 in good general yields of 53-98%. A synthetic potential of the obtained delta-diketones has been demonstrated by heterocyclization with hydrazine into substututed 5,6-dihydro-4H-1,2-diazepine.

Automated summary

The reaction between linear conjugated enynones and 3-oxo-3-phenylpropanenitrile yields polyfunctional delta-diketones as regioselective Michael addition products. The obtained delta-diketones can further undergo heterocyclization with hydrazine, demonstrating their synthetic potential.