Mild and efficient synthesis oftrans-3-aryl-2-nitro-2,3-dihydrobenzofurans on water

Abstract

<p>A protocol to prepare <italic>trans</italic>-3-aryl-2-nitro-2,3-dihydrobenzofurans has been developed on water. The protocol avoids the use of toxic solvents, tedious work-up procedures, and chromatographic separation.</p>

Developments and applications of α-bromonitrostyrenes in organic syntheses

“…In 2020, Feng et al presented a protocol for the construction of diastereoselective trans -3-aryl-2-nitro-2,3-dihydrobenzofurans 54 under basic conditions ( Scheme 24 ). 53 A diverse range of ( Z )-bromonitrostyrenes 1, containing aryl, naphthyl and thiophenyl moieties reacted smoothly with sesamol 53 in water as a green solvent to form dihydrofurans in excellent yields. All products were purified only by a simple filtration procedure and could also be synthesized in the Gram-scale (1.20 g, 94%).…”

Bromonitroalkenes as efficient intermediates in organic synthesis

“…The structure and stereochemistry of the products were confirmed using X-ray crystallography. 35 In this context, Dong et al described a stereoselective method for synthesizing dihydrofuranoindoles, which are compounds containing fused furan and indole rings. The method involves an organocatalytic cascade reaction between hydroxyindoles 72/74/76/78 and bromonitrostyrenes 1 using the bifunctional squaramide catalyst Cat-12 (Scheme 32).…”

DBU Promoted Polysubstituted Arene Formation via a Michael Addition/Cyclization/Elimination Cascade Reaction

“…Recently, the easily accessible α-brominated and chlorinated nitrostyrenes 1 and 2 [ 13 , 14 ] were emerged as powerful C 2 synthons in the synthesis of different ring systems ( Figure 1 a). In particular, with the utilization of different C 3 synthons, a series of polysubstituted heteroarenes were constructed through (3 + 2) cyclization process, including furans [ 15 , 16 , 17 , 18 ], pyrazoles [ 19 , 20 , 21 ], imidazoles [ 22 ], triazoles [ 23 , 24 , 25 ], and pyrroles [ 26 , 27 , 28 , 29 , 30 ]. The versatilities of nitrostyrenes 1-2 were based on the electron deficiency of the double bound and the high reactivity of the leaving group X (X= Cl, Br) [ 31 , 32 , 33 ].…”