Catalyst- and Base-Free Synthesis of Morita–Baylis–Hillman and Rauhut–Currier Adducts of β‑Aminonitroalkenes

A facile,
base- and catalyst-free synthesis of Morita–Baylis–Hillman
and Rauhut–Currier adducts of β-aminonitroalkenes with
different electrophiles such as ethyl glyoxylate, trifluoropyruvate,
ninhydrin, vinyl sulfone, and N-tosylazadiene is
reported. The products are formed in good to excellent yields at room
temperature with a broad substrate scope. The adducts of ninhydrin
and β-aminonitroalkene spontaneously cyclize to fused indenopyrroles.
Gram-scale reactions and synthetic transformations of the adducts
are also reported here.