Morita–Baylis–Hillman Reactions Between Conjugated Nitroalkenes or Nitrodienes and Carbonyl Compounds

Abstract

Morita-Baylis-Hillman (MBH) reactions between conjugated nitroalkenes or nitrodienes and various carbonyl compounds such as glyoxylate, trifluoropyruvate, pyruvaldehyde, oxomalonate, ninhydrin, and formaldehyde have been extensively investigated. The reactions proceeded smoothly in the presence of DMAP (40-100 mol-%) in acetonitrile and in some cases also in that of imidazole (100 mol-%) in CHCl 3 or THF, to provide the multifunctional adducts in good to excellent yields. The reactions catalyzed by DMAP in acetonitrile were superior to the imidazole-catalyzed reactions both in terms of the rate of reaction and in terms of the isolated yields of the MBH adducts. The catalytic roles played by DMAP and imidazole in these reactions, vis-à-vis other MBH cata-

α-Functionalization of Nitroalkenes and Its Applications in Organic Synthesis

“…The MBH reaction of aliphatic nitroalkenes and nitrodienes with formaldehyde, pyruvaldehyde, and ethyl glyoxylate was achieved in moderate to good yields and afforded E-isomers 9 as major products whereas Z-isomers were the major products with ninhydrin and trifluoropyruvate. 21 Since our reactions required stoichiometric amounts of imidazole or DMAP, [20][21] Chen and co-workers developed a procedure which required only catalytic amounts (20 mol% each) of DMAP and a thiourea derivative for the MBH reaction of nitroalkenes 6 with ethylglyoxylate under solvent-free conditions. 22…”

Ninhydrin in synthesis of heterocyclic compounds

“…[107][108][109][110][111] Ninhydrin was used in the design and synthesis of various frameworks, both carbocyclic [112][113][114][115][116][117][118][119] and heterocyclic.…”

Diastereoselective Isomerization of (E)‐β‐Nitroenones into β‐Nitro‐β,γ‐Unsaturated Ketones under Microwave Conditions

“…In fact, to the best of our knowledge, only few examples to achieve this target have been reported in the literature, namely, the nitration of allenyl ketones (Scheme 4a), [5] the elimination of hydrobromic acid from 4-bromo-3-nitro ketones (Scheme 4b), [6] and the Morita-Baylis-Hillman coupling between nitroalkenes and carbonyls in the presence of 4-dimethylaminopyridine (DMAP) or imidazole (Scheme, 4c). [7] Moreover, with the aim of expanding the potential of 2 as building blocks, a variety of polysubstituted pyrroles, key scaffold of many synthetic intermediates and biological active molecules, [8] was prepared.…”

“…As a matter of fact, this approach is the first general method for the synthesis of 2 . In fact, to the best of our knowledge, only few examples to achieve this target have been reported in the literature, namely, the nitration of allenyl ketones (Scheme 4a), [5] the elimination of hydrobromic acid from 4‐bromo‐3‐nitro ketones (Scheme 4b), [6] and the Morita‐Baylis‐Hillman coupling between nitroalkenes and carbonyls in the presence of 4‐dimethylaminopyridine (DMAP) or imidazole (Scheme, 4c) [7] …”