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

Abstract

A facile, base-and catalyst-free synthesis of Morita−Baylis−Hillman and Rauhut−Currier adducts of βaminonitroalkenes with different electrophiles such as ethyl glyoxylate, trifluoropyruvate, ninhydrin, vinyl sulfone, and Ntosylazadiene 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.

Recent progress and prospects in the organocatalytic Morita–Baylis–Hillman reaction

“…It is possible to perform the MBH reaction on β-aminonitroalkenes without the need of a base or catalyst. 58 β-Aminonitroalkene was treated with various electrophiles, including ninhydrin, vinyl sulphone, trifluropyrate, ethyl glyoxylate, and N -tosylazadienes in acetonitrile at room temperature ( Scheme 40 ). Solvent plays a sole role in this reaction.…”

Recent advances in the synthetic applications of Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

“…Subsequent to previous reports on the reaction of pyrrolidine derived nitroalkenes with di- and tricarbonyl compounds, and a one-pot reaction with glyoxylate and aniline, 64 very recently, our group reported a catalyst and base free synthesis of Rauhut–Currier and Morita–Baylis–Hillman adducts of β-aminonitroalkenes. 65 The scope was investigated with different electrophiles such as vinyl sulfone, N -tosylazadiene, ethyl glyoxylate and ninhydrin. The functional group diversity and synthetic efficiency was shown by employing differently substituted aminonitroalkenes and electrophiles, scale up reactions and synthetic transformations (Scheme 54).…”