DBU-Mediated Addition of α‑Nitroketones to α‑Cyano-enones and α,β-Unsaturated α‑Ketoesters: Synthesis of Dihydrofurans and Conjugated Dienes

1,8-Diazabicyclo­[5.4.0]­undec-7-ene-mediated reactions of α-nitroketones with α-cyano-enones and α,β-unsaturated α-ketoesters have been developed. The products, namely, dihydrofurans and conjugated dienes, were isolated in moderate to good yields, and a range of substitutions were tolerated.