One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

Abstract

β-Nitrostyrenes underwent a Diels–Alder reaction with Danishefsky’s diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated-5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated-4-nitrophenols. The reaction of nitrostyrenes with Danishefsky’s diene could be conducted in one pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group, e.g., a thienyl group could be introduced into the nitrophenol framework.

Nitroacetonitrile and Its Synthetic Equivalents

“…39 The obtained alkenes 8 are highly electron-deficient and can thus serve as reactive dienophiles, efficiently undergoing Diels−Alder reaction under mild reaction conditions with dienes, such as 2,3-dimethylbutadine 11 (Scheme 5) 31,40 and 1,3-cyclopentadiene. 41 Because the nitro group is readily eliminated as a nitrous acid, 18,42,43 the cycloadduct 12 can be readily converted to functionalized biphenyls 13 upon treatment of 12 with base under solvent-free conditions in the presence of oxygen (Scheme 5). 40 Nitroalkenes are known to exhibit dual behavior in the Diels−Alder reaction: as a dienophile and as a heterodiene.…”

Unusual Reactivities of ortho-Hydroxy-β-nitrostyrene

“…In the case of a nitroalkene, the resonance effect besides the induced effect generates biased electron-density of the scaffold and facilitates reactions such as nucleophilic addition and cycloaddition. Indeed, β-nitrostyrene serves as a good electrophile for the conjugate addition to afford α-substituted β-(nitro)ethylbenzenes [ 2 ], and serves as a good dienophile for the Diels–Alder reaction [ 3 , 4 , 5 ] or dipolarophile for cycloaddition with 1,3-dipole [ 6 , 7 , 8 ] to construct versatile cyclic systems. Nitrostyrenes also undergo denitrative cross-coupling reactions, affording disubstituted alkenes [ 9 ].…”