Unanticipated Three-Component Cascade and Sequential Cyclization: Highly Diastereoselective Synthesis of Polyfunctionalized Cyclohexanes.

Herein, we reported a DBU-catalyzed cascade and sequential [1 + 2 + 3] annulation of malononitrile with α,β-unsaturated ketones to access polyfunctionalized cyclohexanes with high yield and excellent diastereoselectivity (>93% yield, >19:1 dr). Intriguingly, this appears to be the new strategy for using α,β-unsaturated ketones either as 2C or 3C synthon to react with dinucleophile 1C synthon to construct six-membered carbocycles in one-pot manner. In addition, these synthesized compounds suppressed the growth of phytopathogenic fungi in vitro. Among them, compound 3l exhibited excellent and broad antifungal activity, which possesses potential as an agricultural antifungal agent.